# Square and Cube Roots Quiz Set 004

### Question 1

What is the least number that should be subtracted from 0.0449 to make it a perfect square?

A

0.04.

B

0.06.

C

0.05.

D

0.004.

Soln.
Ans: a

We know that 0.07 = \$√0.0049\$, so by inspection we can see that 0.0449 - 0.04 will give us 0.0049.

### Question 2

Each book of a shelf has as many pages as is the total number of books in that shelf. If there are 169 pages in all, how many books are there?

A

13.

B

16.

C

24.

D

9.

Soln.
Ans: a

Let the number of books = n. So pages in one book are also n, and therefore, pages in n books = \$n^2\$. We have been given \$n^2 = 169\$, which gives n = 13.

### Question 3

Each car of a garage has as many litres of petrol as is the total number of cars in that garage. If there are 196 litres of petrol in all, how many cars are there?

A

14.

B

12.

C

7.

D

8.

Soln.
Ans: a

Let the number of cars = n. So litres of petrol in one car are also n, and therefore, litres of petrol in n cars = \$n^2\$. We have been given \$n^2 = 196\$, which gives n = 14.

### Question 4

One-third of the cube-root of which number is 0.6?

A

5.832.

B

5.200.

C

5.414.

D

5.173.

Soln.
Ans: a

Let the number be n. So \${1/3} × √^3n\$ = 0.6, which gives \$√^3n\$ = 3 × 0.6 = 1.8. so n = \$1.8^3\$ = 5.832.

### Question 5

What is √0.0081?

A

0.09.

B

0.9.

C

0.009.

D

0.0009.

Soln.
Ans: a

We can see that 0.09 × 0.09 = 0.0081, so square root is 0.09.