Brain Champs-for Class 9

1. If x/0.1= m,what will be x*0.01?

0.001m

0.1m

10m

1000m

0.0001m

When we have the equation x/0.1 = m, we can rearrange it to x = 0.1m.
Now, if we multiply x by 0.01, we get (0.1m)(0.01) = 0.001m.
Therefore, the answer is 0.001m.

Explanation

When we have the equation x/0.1 = m, we can rearrange it to x = 0.1m.
Now, if we multiply x by 0.01, we get (0.1m)(0.01) = 0.001m.
Therefore, the answer is 0.001m.

2. The square root of 27225 lies between?

50-60

120-130

160-170

500-600

570-670

The square root of 27225 is approximately 165. Therefore, it lies between the range of 160-170.

Explanation

The square root of 27225 is approximately 165. Therefore, it lies between the range of 160-170.

3. If x/y=70,x/2y=?

35

68

72

140

70

If x/y = 70, it means that x is 70 times greater than y. To find x/2y, we can substitute the value of x/y into the equation. Therefore, x/2y = (70y)/2y = 35. This means that x/2y is equal to 35.

Explanation

If x/y = 70, it means that x is 70 times greater than y. To find x/2y, we can substitute the value of x/y into the equation. Therefore, x/2y = (70y)/2y = 35. This means that x/2y is equal to 35.

4. x and y are 2 different numbers.What can be added to 6x to get 9y?

3y

3x

9y-3x

9y+3x

It is not possible to get 9y as 6x and 9y are not like terms

To get 9y, we need to add 9y-6x. This is because 6x and 9y are not like terms, so we cannot simply add them together. Therefore, the correct answer is 9y-3x.

Explanation

To get 9y, we need to add 9y-6x. This is because 6x and 9y are not like terms, so we cannot simply add them together. Therefore, the correct answer is 9y-3x.

5. What is the measure of angle DCB in the paralleogram ABCD given below?If angleDCA=31 and angle DAB=44?

62

75

88

105

120

In a parallelogram, opposite angles are equal. Therefore, angle DCB is equal to angle DAB, which is given as 44 degrees.

Explanation

In a parallelogram, opposite angles are equal. Therefore, angle DCB is equal to angle DAB, which is given as 44 degrees.

6. The sum of 3 numbers is 'k'.Each number is incresed by 15 and then the resulting number are doubled.What would be the sum of the new numbers?

2k+15

2k+30

2k+90

6k+30

6k+90

When each number is increased by 15, the sum of the three new numbers would be 3k + 45. Then, when these resulting numbers are doubled, each number becomes 2 times its original value. Therefore, the sum of the new numbers would be 2(3k + 45), which simplifies to 6k + 90.

Explanation

When each number is increased by 15, the sum of the three new numbers would be 3k + 45. Then, when these resulting numbers are doubled, each number becomes 2 times its original value. Therefore, the sum of the new numbers would be 2(3k + 45), which simplifies to 6k + 90.

7. Adding 5% of a number to itself is the same as multiplying the number by .............

1.05

1.5

5

105

1.075

Adding 5% of a number to itself is equivalent to multiplying the number by 1.05. This is because 5% of a number can be calculated by multiplying the number by 0.05. Adding this result to the original number is the same as multiplying the original number by 1.05.

Explanation

Adding 5% of a number to itself is equivalent to multiplying the number by 1.05. This is because 5% of a number can be calculated by multiplying the number by 0.05. Adding this result to the original number is the same as multiplying the original number by 1.05.

8. The volume of a cube is 64cm cube.What is the sum of lengths of all its edges?

24cm

32cm

48cm

64cm

52cm

The volume of a cube is found by multiplying the length of one of its edges by itself three times. In this case, if the volume is 64cm^3, then the length of one edge is the cube root of 64, which is 4cm. Since a cube has 12 edges of equal length, the sum of the lengths of all its edges would be 12 times the length of one edge, which is 12 * 4cm = 48cm.

Explanation

The volume of a cube is found by multiplying the length of one of its edges by itself three times. In this case, if the volume is 64cm^3, then the length of one edge is the cube root of 64, which is 4cm. Since a cube has 12 edges of equal length, the sum of the lengths of all its edges would be 12 times the length of one edge, which is 12 * 4cm = 48cm.

9. Which is 'not' a integer?

(3)-5

(-3)-5

(1/3)-5

(1+3)-5

(1-3)-5

The expression (3)-5 is not a valid mathematical expression. The correct way to write it would be 3 - 5. Therefore, (3)-5 is not an integer.

Explanation

The expression (3)-5 is not a valid mathematical expression. The correct way to write it would be 3 - 5. Therefore, (3)-5 is not an integer.

10. (3)20+(3)20+(3)20+

(9)60

(9)20

(9)40

(3)60

(3)21

The given expression consists of multiple terms, each enclosed in parentheses and separated by a plus sign. Each term is a multiplication of a number inside the parentheses with a number outside the parentheses. The expression can be simplified by performing the multiplications first and then adding the results. In this case, we have (3)20 + (3)20 + (3)20, which simplifies to 60 + 60 + 60 = 180. Therefore, the correct answer is 180.

Explanation

The given expression consists of multiple terms, each enclosed in parentheses and separated by a plus sign. Each term is a multiplication of a number inside the parentheses with a number outside the parentheses. The expression can be simplified by performing the multiplications first and then adding the results. In this case, we have (3)20 + (3)20 + (3)20, which simplifies to 60 + 60 + 60 = 180. Therefore, the correct answer is 180.