This set of Aptitude Questions and Answers (MCQs) focuses on “Square Roots and Cube Roots – Set 2”.
1. Find the cube root of 5832.
a) 18
b) 16
c) 26
d) 28
View Answer
Explanation: 5832 = 8*27*27 = 23*36. Therefore, \(\sqrt[3]{5836}=\sqrt[3]{2^3*3^6}\)=18.
2. Find the least number that should be multiplied to 2304 to obtain a perfect cube.
a) 8
b) 6
c) 7
d) 5
View Answer
Explanation: 2304 = 9*16*16 = 28 * 32. Therefore, the number should be multiplied by 2*3 = 6, to obtain a perfect cube.
3. Find the cube root of 0.000343.
a) 0.7
b) 0.007
c) 0.07
d) 0.1508
View Answer
Explanation: 0.000343 = 343*10-6.
\(\sqrt[3]{0.000343}=\sqrt[3]{343*10^{-6}}\)=7*10-2=0.07.
4. Find the value of \(\sqrt[3]{\sqrt{0.000729}}\).
a) 0.2
b) 0.4
c) 0.03
d) 0.3
View Answer
Explanation: \(\sqrt{0.000729}=\sqrt{729*10^{-6}}\)=27*10-3.
\(\sqrt[3]{\sqrt{0.000729}}=\sqrt[3]{27*10^{-3}}\)=3*10-1=0.3.
5. Find the smallest number by which 21296 be divided to make it a perfect cube.
a) 2
b) 3
c) 4
d) 6
View Answer
Explanation: 21296 = 4*4*11*11*11 = 24*113.
Therefore, the number should be divided by 2 to make it a perfect cube.
6. Find the smallest number that should be subtracted from 1730, so that the obtained number is perfect cube.
a) 12
b) 2
c) 8
d) 14
View Answer
Explanation: We know that 113 = 1331 and 123 = 1728.
1730 – 1728 = 2.
Therefore, the number to be subtracted is 2.
7. Find the smallest number that should be multiplied to 686 to make it a perfect cube.
a) 8
b) 3
c) 4
d) 12
View Answer
Explanation: 686 = 2*73.
Therefore, the smallest number to be multiplied is 4.
8. Find the smallest number that should be added to 2190 to make it a perfect cube.
a) 29
b) 21
c) 13
d) 7
View Answer
Explanation: We know that, 123 = 1728 and 133 = 2197.
2197 – 2190 = 7.
Therefore, the smallest number to be added is 7.
9. Find the value of \(\sqrt[3]{\frac{0.729*0.027*343}{729*0.216}}\).
a) 0.35
b) 0.5
c) 0.68
d) 0.27
View Answer
Explanation: \(\sqrt[3]{\frac{0.729*0.027*343}{729*0.216}}=\sqrt[3]{\frac{729*27*343}{729*216*1000}} = \frac{3*7}{6*10}\)=0.35.
10. Find the value of \(\sqrt[3]{134^3+82^3+246*134^2+402*82^3}\).
a) 6
b) 216
c) 7
d) 343
View Answer
Explanation: We know that (a+b)3=a3+b3+3a2b+3ab2.
\(\sqrt[3]{134^3+82^3+246*134^2+402*82^2}=\sqrt[3]{134^3+82^3+3*134^2*82+3*134*82^2}=\sqrt[3]{(134+82)^3}\)=216.
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