Math Day Competition (G9 Al Tamayoz )

1) 125 x 10 ^-2 as a basic numeral is

1.25

12.5

0.125

12500

The given expression, 125 x 10 - 2, can be simplified by performing the multiplication first. 125 multiplied by 10 is equal to 1250. Then, subtracting 2 from 1250 gives us 1248. Therefore, the basic numeral for 125 x 10 - 2 is 1248.

Explanation

The given expression, 125 x 10 - 2, can be simplified by performing the multiplication first. 125 multiplied by 10 is equal to 1250. Then, subtracting 2 from 1250 gives us 1248. Therefore, the basic numeral for 125 x 10 - 2 is 1248.

2) A man is paid Dh16.75 an hour for a 42 hour week , his weekly wage is

Dh702.5

Dh705.3

Dh703.5

Dh703.05

The man is paid Dh16.75 per hour for a 42-hour week. To find his weekly wage, we multiply the hourly rate by the number of hours worked. Dh16.75 multiplied by 42 equals Dh703.5. Therefore, his weekly wage is Dh703.5.

Explanation

The man is paid Dh16.75 per hour for a 42-hour week. To find his weekly wage, we multiply the hourly rate by the number of hours worked. Dh16.75 multiplied by 42 equals Dh703.5. Therefore, his weekly wage is Dh703.5.

3) 0.0085 as scientific notation is

8.5 × 10 3

8.5 × 10 - 3

0.85 × 10 3

85 × 10 - 3

The given number, 0.0085, can be written in scientific notation as 8.5 × 10^-3. In scientific notation, the number is written in the form of a decimal number multiplied by a power of 10. In this case, the decimal number is 8.5 and it is multiplied by 10 raised to the power of -3, which means the decimal point is moved 3 places to the left. This is the correct answer because it represents the original number in a concise and standardized format.

Explanation

The given number, 0.0085, can be written in scientific notation as 8.5 × 10^-3. In scientific notation, the number is written in the form of a decimal number multiplied by a power of 10. In this case, the decimal number is 8.5 and it is multiplied by 10 raised to the power of -3, which means the decimal point is moved 3 places to the left. This is the correct answer because it represents the original number in a concise and standardized format.

4) A woman is paid a salary of Dh39133.5 per year , his weekly wage is ( one year = 52.178 weeks )

Dh570

Dh750

Dh507

Dh705

The woman's yearly salary is Dh39133.5, and there are 52.178 weeks in a year. To find her weekly wage, we divide her yearly salary by the number of weeks in a year: Dh39133.5 / 52.178 = Dh750. Therefore, her weekly wage is Dh750.

Explanation

The woman's yearly salary is Dh39133.5, and there are 52.178 weeks in a year. To find her weekly wage, we divide her yearly salary by the number of weeks in a year: Dh39133.5 / 52.178 = Dh750. Therefore, her weekly wage is Dh750.

5) For 12 tins of tuna at Dh3.95 , I paid

Dh74.4

Dh47

Dh47.4

Dh44.7

The correct answer is Dh47.4 because if each tin of tuna costs Dh3.95, then 12 tins would cost 12 x Dh3.95 = Dh47.4.

Explanation

The correct answer is Dh47.4 because if each tin of tuna costs Dh3.95, then 12 tins would cost 12 x Dh3.95 = Dh47.4.

6) The commission of 8% paid on sales of Dh3000 is

Dh24.0

Dh24

Dh2.40

Dh240

The commission of 8% paid on sales of Dh3000 is Dh240 because 8% of Dh3000 is equal to (8/100) * Dh3000 = Dh240.

Explanation

The commission of 8% paid on sales of Dh3000 is Dh240 because 8% of Dh3000 is equal to (8/100) * Dh3000 = Dh240.

7) Hamad was given a 25% discount , if the price of an item is Dh85 , he is paid

Dh36.75

Dh63.75

Dh63.5

Dh67.35

If Hamad was given a 25% discount on the price of the item, it means he paid only 75% of the original price. To find the amount he paid, we can multiply the original price (Dh85) by 75% (0.75). Dh85 * 0.75 = Dh63.75. Therefore, the correct answer is Dh63.75.

Explanation

If Hamad was given a 25% discount on the price of the item, it means he paid only 75% of the original price. To find the amount he paid, we can multiply the original price (Dh85) by 75% (0.75). Dh85 * 0.75 = Dh63.75. Therefore, the correct answer is Dh63.75.

8) The simple interest for Dh4900 at 8% pa for 4 years is : ( I=PRT )

Dh1685

Dh1568

Dh1658

Dh1586

The formula for calculating simple interest is I = PRT, where I is the interest, P is the principal amount, R is the rate of interest, and T is the time period. In this case, the principal amount is Dh4900, the rate of interest is 8% per annum, and the time period is 4 years. Plugging in these values into the formula, we get I = 4900 * 0.08 * 4 = Dh1568. Therefore, the correct answer is Dh1568.

Explanation

The formula for calculating simple interest is I = PRT, where I is the interest, P is the principal amount, R is the rate of interest, and T is the time period. In this case, the principal amount is Dh4900, the rate of interest is 8% per annum, and the time period is 4 years. Plugging in these values into the formula, we get I = 4900 * 0.08 * 4 = Dh1568. Therefore, the correct answer is Dh1568.

9) A man works a 35 hour week for an hourly rate of Dh20.5 plus an extra allowance of 75 fils per hour , his total wage is :

Dh743.75

Dh437.75

Dh743.57

Dh743.5

The man works for 35 hours a week, and his hourly rate is Dh20.5. In addition to that, he receives an extra allowance of 75 fils per hour. To calculate his total wage, we need to multiply his hourly rate by the number of hours he works, and then add the extra allowance. Hourly rate = Dh20.5 x 35 = Dh717.5 Extra allowance = 75 fils x 35 = Dh26.25 Total wage = Hourly rate + Extra allowance = Dh717.5 + Dh26.25 = Dh743.75 Therefore, the correct answer is Dh743.75.

Explanation

The man works for 35 hours a week, and his hourly rate is Dh20.5. In addition to that, he receives an extra allowance of 75 fils per hour. To calculate his total wage, we need to multiply his hourly rate by the number of hours he works, and then add the extra allowance. Hourly rate = Dh20.5 x 35 = Dh717.5 Extra allowance = 75 fils x 35 = Dh26.25 Total wage = Hourly rate + Extra allowance = Dh717.5 + Dh26.25 = Dh743.75 Therefore, the correct answer is Dh743.75.

10) The simple interest rate for Dh2500 to earn Dh750 interest for 3 years

5%

8%

10%

7.5%

To calculate the simple interest, we can use the formula: I = PRT, where I is the interest, P is the principal amount, R is the interest rate, and T is the time period. In this case, we are given that the principal amount is Dh2500 and the interest is Dh750. We need to find the interest rate. Plugging in the given values into the formula, we get 750 = 2500 * R * 3. Solving for R, we find that R = 0.1 or 10%. Therefore, the correct answer is 10%.

Explanation

To calculate the simple interest, we can use the formula: I = PRT, where I is the interest, P is the principal amount, R is the interest rate, and T is the time period. In this case, we are given that the principal amount is Dh2500 and the interest is Dh750. We need to find the interest rate. Plugging in the given values into the formula, we get 750 = 2500 * R * 3. Solving for R, we find that R = 0.1 or 10%. Therefore, the correct answer is 10%.

11) Ahmed receives Dh18.5 per hour for the first 7 hours , and time and – a – half for next hours , if Ahmed works 12 hours he receives :

Dh826.25

Dh268.25

Dh286.25

Dh628.25

Ahmed receives Dh18.5 per hour for the first 7 hours, which means he earns 7 * Dh18.5 = Dh129.5 for those hours.
For the remaining 5 hours, he receives time and a half, which means he earns Dh18.5 * 1.5 = Dh27.75 per hour.
So, for the next 5 hours, he earns 5 * Dh27.75 = Dh138.75.
Adding up the earnings for the first 7 hours and the next 5 hours, Ahmed receives a total of Dh129.5 + Dh138.75 = Dh268.25 if he works 12 hours.

Explanation

Ahmed receives Dh18.5 per hour for the first 7 hours, which means he earns 7 * Dh18.5 = Dh129.5 for those hours.
For the remaining 5 hours, he receives time and a half, which means he earns Dh18.5 * 1.5 = Dh27.75 per hour.
So, for the next 5 hours, he earns 5 * Dh27.75 = Dh138.75.
Adding up the earnings for the first 7 hours and the next 5 hours, Ahmed receives a total of Dh129.5 + Dh138.75 = Dh268.25 if he works 12 hours.

12) When simplifying an algebraic expression, combining like terms is essential. Terms that share the same variable and the same ________ can be combined through addition or subtraction to simplify the expression.

In algebra, like terms are terms that contain the same variables raised to the same power (or exponent). Simplifying expressions by combining like terms involves adding or subtracting the coefficients (numeric factors) of these terms while keeping the variable part unchanged. This process is fundamental in algebra to reduce and solve equations more effectively.

Explanation

In algebra, like terms are terms that contain the same variables raised to the same power (or exponent). Simplifying expressions by combining like terms involves adding or subtracting the coefficients (numeric factors) of these terms while keeping the variable part unchanged. This process is fundamental in algebra to reduce and solve equations more effectively.

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13) Calculate the final price if successive discounts of 20% and 10% were applied to a price of Dh250 احسب السعر النهائي بعد تخفيض متتالي ( تخفيضين متتابعين ) بنسبة 20% و 10% لسلعة سعرها 250 درهم

The final price can be calculated by applying the first discount of 20% to the original price of Dh250. This would result in a discounted price of Dh200. Then, the second discount of 10% is applied to the discounted price of Dh200. This would result in a final price of Dh180.

Explanation

The final price can be calculated by applying the first discount of 20% to the original price of Dh250. This would result in a discounted price of Dh200. Then, the second discount of 10% is applied to the discounted price of Dh200. This would result in a final price of Dh180.

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14) Which is the least expensive , Red label tea costs Dh7.8 for 936 g or Lipton tea costs Dh9.5 for 1425 g . أيهما الأرخص شاي ريد ليبل سعر 936 جرام يساوي 7.8 درهم أو شاي ليبتون سعر 1425 جرام يساوي 9.5 درهم .

The correct answer is "Lipton tea." Lipton tea costs Dh9.5 for 1425 g, while Red label tea costs Dh7.8 for 936 g. Since Lipton tea costs more for a larger quantity, it can be concluded that Red label tea is the least expensive option.

Explanation

The correct answer is "Lipton tea." Lipton tea costs Dh9.5 for 1425 g, while Red label tea costs Dh7.8 for 936 g. Since Lipton tea costs more for a larger quantity, it can be concluded that Red label tea is the least expensive option.

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15) Ahmed is paid Dh25 for an item , he given a discount of 20% , the original price was

Dh31.25

Dh31.52

Dh30.25

Dh32.25

To find the original price, we need to calculate the price before the 20% discount. We can set up the equation: original price - (20% of original price) = Dh25. Let x be the original price. Therefore, x - (0.2x) = 25. Simplifying the equation, we get 0.8x = 25. Dividing both sides by 0.8, we find x = 31.25. Hence, the original price was Dh31.25.

Explanation

To find the original price, we need to calculate the price before the 20% discount. We can set up the equation: original price - (20% of original price) = Dh25. Let x be the original price. Therefore, x - (0.2x) = 25. Simplifying the equation, we get 0.8x = 25. Dividing both sides by 0.8, we find x = 31.25. Hence, the original price was Dh31.25.

16) The price of a chess set is Dh240 , Ali is paid Dh180 , the percentage of discount is

20%

15%

30%

25%

The correct answer is 25% because the price of the chess set is Dh240 and Ali is paid Dh180, which means he received a discount of Dh60. To find the percentage of discount, we divide the discount amount (Dh60) by the original price (Dh240) and multiply by 100. This gives us a discount of 25%.

Explanation

The correct answer is 25% because the price of the chess set is Dh240 and Ali is paid Dh180, which means he received a discount of Dh60. To find the percentage of discount, we divide the discount amount (Dh60) by the original price (Dh240) and multiply by 100. This gives us a discount of 25%.

17) An item its price : ' Was Dh120 , now Dh78 , the reduction as a percentage of the original price is

25%

45%

30%

35%

The reduction as a percentage of the original price is 35%. This can be calculated by finding the difference between the original price (Dh120) and the reduced price (Dh78), which is Dh42. Then, divide this difference by the original price and multiply by 100 to get the percentage. In this case, (42/120) * 100 = 35%.

Explanation

The reduction as a percentage of the original price is 35%. This can be calculated by finding the difference between the original price (Dh120) and the reduced price (Dh78), which is Dh42. Then, divide this difference by the original price and multiply by 100 to get the percentage. In this case, (42/120) * 100 = 35%.

18) The answer of ( 2.1 m 10³ ) + ( 2.6 m 10 ⁴) as a scientific notation is

28100

2.81 × 10 3

2.81 × 10 - 4

2.81 × 10 4

The given expression (2.1 × 10^3) + (2.6 × 10^4) represents the sum of two numbers in scientific notation. To add numbers in scientific notation, we need to make sure that the exponents are the same. In this case, both numbers have the same exponent of 4. When we add the numbers, we add the coefficients (2.1 + 2.6 = 4.7) and keep the exponent the same (10^4). Therefore, the sum is 4.7 × 10^4, which is equivalent to 2.81 × 10^4 when rounded to two decimal places.

Explanation

The given expression (2.1 × 10^3) + (2.6 × 10^4) represents the sum of two numbers in scientific notation. To add numbers in scientific notation, we need to make sure that the exponents are the same. In this case, both numbers have the same exponent of 4. When we add the numbers, we add the coefficients (2.1 + 2.6 = 4.7) and keep the exponent the same (10^4). Therefore, the sum is 4.7 × 10^4, which is equivalent to 2.81 × 10^4 when rounded to two decimal places.

19) Arrange in descending order ( from largest to smallest ) : 1.8 x 10⁰ , 1.08 x 10^{- 1} , 1.8 x 10 , 1.88 x 10 ^{- 1}

The given answer correctly arranges the numbers in descending order based on their magnitude. The number with the largest magnitude is 1.8 x 10^0, followed by 1.8 x 10, then 1.88 x 10^-1, and finally 1.08 x 10^-1. This arrangement is correct because the exponent of 10 determines the magnitude of the number, with larger exponents indicating larger magnitudes.

Explanation

The given answer correctly arranges the numbers in descending order based on their magnitude. The number with the largest magnitude is 1.8 x 10^0, followed by 1.8 x 10, then 1.88 x 10^-1, and finally 1.08 x 10^-1. This arrangement is correct because the exponent of 10 determines the magnitude of the number, with larger exponents indicating larger magnitudes.

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