square root and cube root aptitude questions – Free Online Questions and Answers

The cube root of .000216 is:

A.	.6	B.	.06
C.	77	D.	87

Answer & Explanation

Answer: Option B

Explanation:

(.000216)^1/3	=		216		1/3
			10⁶

=		6 x 6 x 6		1/3
		10² x 10² x 10²

=	6
	10²

=	6
	100

= 0.06

What should come in place of both x in the equation	x	=	162	.
	128		x

A.	12	B.	14
C.	144	D.	196

Answer & Explanation

Answer: Option A

Explanation:

Let	x	=	162
	128		x

Then x² = 128 x 162

= 64 x 2 x 18 x 9

= 8² x 6² x 3²

= 8 x 6 x 3

= 144.

x = 144 = 12.

The least perfect square, which is divisible by each of 21, 36 and 66 is:

A.	213444	B.	214344
C.	214434	D.	231444

Answer & Explanation

Answer: Option A

Explanation:

L.C.M. of 21, 36, 66 = 2772.

Now, 2772 = 2 x 2 x 3 x 3 x 7 x 11

To make it a perfect square, it must be multiplied by 7 x 11.

So, required number = 2² x 3² x 7² x 11² = 213444

1.5625 = ?

A.	1.05	B.	1.25
C.	1.45	D.	1.55

Answer & Explanation

Answer: Option B

Explanation:

   1|1.5625( 1.25
    |1
    |-------
  22| 56
    | 44
    |-------
 245| 1225
    | 1225
    |-------
    |    X
    |-------

1.5625 = 1.25.

If 35 + 125 = 17.88, then what will be the value of 80 + 65 ?

A.	13.41	B.	20.46
C.	21.66	D.	22.35

Answer & Explanation

Answer: Option D

Explanation:

35 + 125 = 17.88

35 + 25 x 5 = 17.88

35 + 55 = 17.88

85 = 17.88

5 = 2.235

80 + 65 = 16 x 5 + 65

= 45 + 65

= 105 = (10 x 2.235) = 22.35