Square Root and Cube Root - Quantitative Aptitude (MCQ) questions

1)   Two-third of two-fifth of three-fourth of a number is 36. What is the square root of four-fifth of that number?
- Published on 15 Apr 16

a. 9
b. 12
c. 14
d. 16
e. None of these
Answer  Explanation 

ANSWER: 12

Explanation:
We have, 2/3 * 2/5 * 3/4 * X = 36
X = 180
Now, 4/5 * X ===> 4/5 * 180 = 144
√144 = 12


2)   How many two-digit numbers satisfy the following property given below:
The last digit (unit's digit) of the square of the two-digit number is 8?

- Published on 13 Apr 16

a. 4
b. 12
c. 15
d. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Any number ending in 8 can never be a perfect square. Hence, the answer is none of these.


3)   Two-third of two-fifth of three-fourth of a number is 36. What is the square root of four-fifth of that number?
- Published on 05 Apr 16

a. 9
b. 12
c. 14
d. 16
e. None of these
Answer  Explanation 

ANSWER: 12

Explanation:
We have, 2/3 * 2/5 * 3/4 * X = 36
X = 180
Now, 4/5 * X = 4/5 * 180 = 144
144 = 12


4)   If √10 = 3.16, find the value of If √5/2
- Published on 31 Mar 16

a. 1.30
b. 1.58
c. 2.03
d. 2.15
Answer  Explanation 

ANSWER: 1.58

Explanation:
(5/2) =√(5×2/2×2)= √(10)/2 =3.16/2 = 1.58


5)   The cube root of .000343 is
- Published on 25 Mar 16

a. 0.7
b. 0.07
c. 0.007
d. None of these
Answer  Explanation 

ANSWER: 0.07

Explanation:
(.000343)1/3
= (343/106)1/3
= (7*7*7/ 102*102*102)1/3
= 7/102
= 7/100 = 0.07


6)   Given that √12 = 3.464 and √120 = 10.95, find the value of √1.2 + √1200 + √0.012.
- Published on 22 Mar 16

a. 32.164
b. 35.844
c. 36.164
d. 37.304
Answer  Explanation 

ANSWER: 35.844

Explanation:
Given exp. = √1.2 +√1200 +√0.0120 = √120/100 +√12*100 + √120/10000
= (√120)/10 + √12 * 10 + (√120)/100 = 10.95/10 + 3.464 * 10 + 10.95/100
= 1.095 + 34.64 + 0.1095
= 35.8445


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