Class 9 Math Masters: Conquer The Quiz Challenge!
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Are you ready to embark on an exciting journey through the Class 9 Math Quiz? Mathematics can seem like a complex puzzle, but it's a captivating world of patterns and logic waiting to be explored. By understanding its applications and recognizing the elegance of solving equations, you can unlock its true potential. This quiz is designed to gauge your knowledge of ninth-grade math concepts and challenge your problem-solving skills. Are you prepared to take on the challenge and demonstrate your mathematical prowess? Let's dive in and see how well you fare in this fascinating world of numbers and equations
Class 9 Math Quiz Questions and Answers
- 1.
A is 40% of B. What percentage is B of A?
- A.
60%
- B.
140%
- C.
250%
- D.
160%
Correct Answer
C. 250%Explanation
If A is 40% of B, this means A = 0.4B. To find what percentage B is of A, you rearrange this equation to solve for B in terms of A:B = A / 0.4This can be rewritten as:B = 2.5ATo convert the factor 2.5 into a percentage, you multiply it by 100:2.5 x 100 = 250%Thus, B is 250% of A, indicating that B is more than twice the size of A.Rate this question:
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- 2.
X+5=10. Then x equals:
- A.
5
- B.
10
- C.
15
- D.
-5
Correct Answer
A. 5Explanation
To solve the equation x + 5 = 10 for x, you need to isolate x on one side. Subtract 5 from both sides of the equation:
x + 5 - 5 = 10 - 5
This simplifies to:
x = 5
Therefore, x equals 5.Rate this question:
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- 3.
X2+4x+3=0; Then x equals:
- A.
2 or 3
- B.
-1 or -3
- C.
1 or 3
- D.
5 or -1
Correct Answer
B. -1 or -3Explanation
To solve the quadratic equation x^2 + 4x + 3 = 0, you can factorize it:
(x + 3)(x + 1) = 0
Setting each factor equal to zero gives:
x + 3 = 0
Solving for x, x = -3
x + 1 = 0
Solving for x, x = -1
Thus, the solutions for x are -1 and -3. These are the values that make the original equation true when substituted back into it.Rate this question:
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- 4.
What is the next number in the sequence: 3, 7, 15, 31, ?
- A.
47
- B.
63
- C.
72
- D.
58
Correct Answer
B. 63Explanation
The given sequence is increasing, and each number is obtained by doubling the previous number and then adding 1.
Starting with 3:
3 * 2 + 1 = 7
7 * 2 + 1 = 15
15 * 2 + 1 = 31
To find the next number, we apply the same pattern:
31 * 2 + 1 = 63
So, the next number in the sequence is 63.Rate this question:
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- 5.
Y2+ 4=20. Then y equals:
- A.
4 only
- B.
-4 only
- C.
4 or -4
- D.
16
Correct Answer
C. 4 or -4Explanation
To solve the equation y^2 + 4 = 20, first subtract 4 from both sides:
y^2 + 4 - 4 = 20 - 4
This simplifies to:
y^2 = 16
Next, find y by taking the square root of both sides. Remember, squaring a number results in a positive value, and the square root of a positive number has both a positive and negative solution:
y = sqrt(16)
This gives:
y = 4 and y = -4
Therefore, y equals both 4 and -4.Rate this question:
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- 6.
The price of an item increases by 20% and then decreases by 20%. So the price has:
- A.
Increased by 4%
- B.
Decreased by 4%
- C.
Increased by 0%
- D.
Increased by 40%
Correct Answer
B. Decreased by 4%Explanation
When the price of an item increases by 20% and then decreases by 20%, the final price does not return to the original because the base amounts for each percentage calculation differ.
Suppose the original price of the item is 100 dollars.
After a 20% increase, the new price becomes:
100 + 20% of 100 = 100 + 20 = 120 dollars
Then a 20% decrease on the new price (120 dollars) is calculated:
120 - 20% of 120 = 120 - 24 = 96 dollars
Comparing the final price (96 dollars) with the original price (100 dollars), there is a decrease of:
100 - 96 = 4 dollars
As a percentage of the original price, this decrease is:
(4 / 100) x 100% = 4%
So, the price has decreased by 4%.Rate this question:
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- 7.
The ratio of girls: boys in a school is 5:7. If there are 525 girls, how many boys are there?
- A.
375
- B.
625
- C.
735
- D.
325
Correct Answer
C. 735Explanation
The ratio of girls to boys in the school is 5:7. This means for every 5 girls, there are 7 boys. Given there are 525 girls, we first determine how many times the part of the ratio (5) fits into the actual number of girls (525).
Calculate the multiplier for the ratio:
525 (number of girls) / 5 (girl ratio part) = 105
Now, use this multiplier to find the number of boys:
Multiply the boy ratio part by the multiplier:
7 (boy ratio part) x 105 (multiplier) = 735
Therefore, there are 735 boys in the school.Rate this question:
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- 8.
David and John share $455 in the ratio of 2:3, respectively. How much money does John get?
- A.
$182
- B.
$273
- C.
$91
- D.
$175
Correct Answer
B. $273Explanation
David and John share $455 in the ratio of 2:3. This means for every 2 units that David receives, John receives 3 units. To find out how much money each person gets, you first need to determine the total number of parts into which the money is divided:
Total parts = 2 (David) + 3 (John) = 5 parts
Now, calculate the value of one part:
Value of one part = Total money / Total parts = $455 / 5 = $91
Finally, calculate how much John receives by multiplying the value of one part by the number of parts John receives:
Money John receives = 3 parts x $91/part = $273
Therefore, John receives $273.Rate this question:
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- 9.
X-12y = 0. Then y/x equals:
- A.
1/6
- B.
12
- C.
1/12
- D.
None
Correct Answer
C. 1/12Explanation
To find the ratio of y/x from the equation x-12y = 0, first rearrange the equation to solve for y in terms of x. By moving all terms involving y to one side and all other terms to the opposite side, we get x = 12y. Now, divide both sides of this equation by x to isolate y/x on one side. This gives us y/x = 1/12. Hence, the value of y/x equals 1/12. This is calculated by dividing the coefficient of y by the coefficient of x in the rearranged equation.Rate this question:
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- 10.
Change 3/20 into a decimal:
- A.
0.3
- B.
0.5
- C.
0.15
- D.
1.5
Correct Answer
C. 0.15Explanation
To convert the fraction 3/20 into a decimal, divide the numerator by the denominator. The calculation is performed by dividing 3 by 20. When you divide 3 by 20, you get 0.15. Therefore, the decimal equivalent of the fraction 3/20 is 0.15. This decimal value directly results from the division process, representing the proportion of 3 parts out of a total of 20 parts.Rate this question:
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- 11.
Write 68/0.00001 as an ordinary number.
- A.
6800000
- B.
680000
- C.
68000
- D.
0.00068
Correct Answer
A. 6800000Explanation
To express the fraction 68/0.00001 as an ordinary number, you can perform the division:
68 ÷ 0.00001
Converting the decimal value into fraction, we get:
68 ÷ 1/100000 = 68 * 100000 = 6800000
So, 68/0.00001 is equal to 6,800,000 as an ordinary number.Rate this question:
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- 12.
4*4-2*(-3)+6= ?
- A.
17
- B.
28
- C.
-36
- D.
None
Correct Answer
B. 28Explanation
To solve the expression 4 * 4 - 2 * (-3) + 6 using the BODMAS (Brackets, Order, Division and Multiplication, Addition and Subtraction) rule:
First, evaluate the multiplication and division from left to right:
4 * 4 = 16
-2 * (-3) = 6 (The double negative becomes a positive)
Now, rewrite the expression with the results: 16 + 6 + 6
Finally, perform the addition from left to right: 16 + 6 = 22
22 + 6 = 28
So, 4 * 4 - 2 * (-3) + 6 = 28.Rate this question:
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- 13.
When you reduce $ 80 by 11%, you will get:
- A.
$8.80
- B.
$71.20
- C.
$69
- D.
None
Correct Answer
B. $71.20Explanation
To find the amount remaining after reducing $80 by 11%, first calculate 11% of $80. Multiply 80 by 0.11 to get the reduction amount. This calculation gives 80 * 0.11 = $8.80. Now, subtract this amount from the original $80 to find the reduced total. The calculation is 80 - 8.80 = $71.20. Therefore, when you reduce $80 by 11%, you will get $71.20. This result is achieved by applying the percentage reduction to the original amount and subtracting the calculated value from the original total.Rate this question:
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- 14.
Write 0.67543 correct to 2 significant figures.
- A.
0.68
- B.
0.7
- C.
0.67
- D.
0.70
Correct Answer
A. 0.68Explanation
The given number, 0.67543, has 5 significant figures. Rounding it to 2 significant figures means we need to keep only the first two significant figures and round the rest. The third significant figure, 5, is less than 5, so we round down. Therefore, the correct answer is 0.68.Rate this question:
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- 15.
Simplify 5ab-7ba+4ab=?
- A.
2ab
- B.
-2ab
- C.
16ab
- D.
None
Correct Answer
A. 2abExplanation
The given expression involves adding and subtracting common terms. In this case, we have 5ab, -7ba, and 4ab. By rearranging the terms, we can combine the like terms. The -7ba can be rewritten as -7ab since the order of the variables does not matter. Adding 5ab and 4ab gives us 9ab. Therefore, the simplified expression is 9ab - 7ab, which simplifies further to 2ab.Rate this question:
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- 16.
Solve 4(x+2)=24
- A.
X=11/2
- B.
X=4
- C.
X=-4
- D.
X=16
Correct Answer
B. X=4Explanation
The equation 4(x+2)=24 can be solved by first distributing the 4 to both terms inside the parentheses, resulting in 4x + 8 = 24. Next, we can subtract 8 from both sides of the equation to isolate the variable, giving us 4x = 16. Finally, we divide both sides of the equation by 4 to solve for x, which gives us x = 4.Rate this question:
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- 17.
The sum of the three consecutive even numbers is 222. Find the numbers.
- A.
73,74,75
- B.
74,74,74
- C.
72,74,76
- D.
None
Correct Answer
C. 72,74,76Explanation
The correct answer is 72, 74, 76. The sum of three consecutive even numbers can be found by adding the first even number to the third even number and then adding the result to the second even number. In this case, 72 + 76 + 74 equals 222, which matches the given sum. Therefore, 72, 74, and 76 are the three consecutive even numbers that add up to 222. In the option, 73,74,75, all these are not even numbers. In the other option, 74, 74, 74, consecutive numbers are not present.Rate this question:
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- 18.
The gradient of the line joining (-4,-1) and (4,2) is:
- A.
-3/8
- B.
3/8
- C.
0
- D.
8/3
Correct Answer
B. 3/8Explanation
The gradient of a line is determined by the change in y divided by the change in x between two points on the line. In this case, the change in y is 2 - (-1) = 3 and the change in x is 4 - (-4) = 8. Therefore, the gradient is 3/8.Rate this question:
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- 19.
The gradient of the line y = 4 -2x is:
- A.
4
- B.
2
- C.
-2
- D.
None
Correct Answer
C. -2Explanation
The gradient of a line represents its steepness or slope. In the given equation, y = 4 - 2x, the coefficient of x (-2) represents the slope of the line. Since the coefficient is negative, the line has a negative slope. Therefore, the gradient of the line y = 4 - 2x is -2.Rate this question:
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- 20.
The gradient of the line x+3y=9 is
- A.
3
- B.
1/3
- C.
-1/3
- D.
None
Correct Answer
C. -1/3Explanation
The gradient of a line can be determined by rearranging the equation into the form y = mx + c, where m is the gradient. In this case, rearranging x + 3y = 9 gives y = (-1/3)x + 3, which means that the coefficient of x (-1/3) is the gradient of the line. Therefore, the correct answer is -1/3.Rate this question:
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- 21.
If 2x-3y +4x-7y=0, then the value of y/x is:
- A.
3/5
- B.
5/3
- C.
5/11
- D.
-3/5
Correct Answer
A. 3/5Explanation
2x - 3y + 4x - 7y = 0
Combining like terms:
(2x + 4x) - (3y + 7y) = 0
6x - 10y = 0
Now, let's solve for y in terms of x:
10y = 6x
y = (6/10)x
Simplify the fraction:
y = (3/5)x
So, the value of y/x is 3/5.Rate this question:
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- 22.
If 2x+5y=18 and x=2, what is the value of 4x+5y:
- A.
20
- B.
19
- C.
22
- D.
21
Correct Answer
C. 22Explanation
To find the value of 4x+5y, we substitute the given value of x into the equation 2x+5y=18. This gives us 2(2)+5y=18, which simplifies to 4+5y=18. By subtracting 4 from both sides of the equation, we get 5y=14. Dividing both sides by 5, we find that y=14/5. Now, we substitute the values of x and y into the expression 4x+5y, which gives us 4(2)+5(14/5)=8+14=22. Therefore, the correct answer is 22.Rate this question:
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- 23.
Factor the quadratic expression: x2+x-30:
- A.
(x+5)(x-6)
- B.
(x-5)(x+6)
- C.
(x-6)(x-5)
- D.
None
Correct Answer
B. (x-5)(x+6)Explanation
The given quadratic expression, x^2 + x - 30, can be factorized as (x - 5)(x + 6). This can be determined by finding two numbers that multiply to give -30 and add up to 1, which are -5 and 6 in this case. Therefore, the correct answer is (x - 5)(x + 6).Rate this question:
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- 24.
Change 36 km/h to meters per second:
- A.
20
- B.
10
- C.
36
- D.
None
Correct Answer
B. 10Explanation
To convert kilometers per hour to meters per second, we need to multiply the value by 1000/3600. In this case, 36 km/h is equivalent to 10 meters per second.Rate this question:
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