# Square and Cube Roots Quiz Set 012

### Question 1

How many 4 digit numbers are their whose squares end in 2?

A

0.

B

4.

C

10.

D

21.

Soln.
Ans: a

It is not possible for the square of any number to end in 2, 3, 7 or 8. Hence the answer is 0.

### Question 2

One-fifth of the square-root of which number is 0.6?

A

9.

B

16.

C

4.

D

25.

Soln.
Ans: a

Let the number be n. So \${1/5} × √n\$ = 0.6, which gives \$√n\$ = 5 × 0.6 = 3. so n = \$3^2\$ = 9.

### Question 3

What is √(38880) × √(9720)?

A

19440.

B

19840.

C

19441.

D

19640.

Soln.
Ans: a

We can see that √(38880) × √(9720) is same as √(2 × 2 × 2 × 2 × 2 × 3 × 3 × 3 × 3 × 3 × 5 ) × √(2 × 2 × 2 × 3 × 3 × 3 × 3 × 3 × 5 ) which equals √(28 × 310 × 52), which equals (24 × 35 × 51), which gives 19440.

### Question 4

What is the value of \$x\$ in \$√{0.0196 × x}\$ = 1.4?

A

100.

B

1.

C

10.

D

1000.

Soln.
Ans: a

The given expression can be simplified to \$0.0196 × x\$ = \$1.4^2\$, which gives x = \${1.4^2}/0.0196\$, which is same as \$1.96/0.0196\$ which gives 100.

### Question 5

What is the value of \${√16/5}\$ × \${3/√4}\$ × \${5/√9}\$?

A

2.

B

4.

C

1.

D

5.

Soln.
Ans: a

The given expression can be simplified to \${√2^4/5}\$ × \${3/√2^2}\$ × \${5/√3^2}\$, which is same as \${2^2/5}\$ × \${3/2}\$ × \${5/3}\$, which cancels to 2.