Square and Cube Root- Aptitude Questions and Answers

 Find the value of the following √156.25 + √0.0081 - √0.0361 ? A) 13.4 B) 15.4 C) 12.4 D) 17.4 Correct Answer : 12.4 Explanation :√156.25 + √0.0081 - √0.0361 =12.5+0.09-0.19 =12.4 Post/View Answer Post comment Cancel Thanks for your comment.! Write a comment(Click here) ...
 Find the least number which when multiplied with 74088 will make it a perfect square ? A) 42 B) 44 C) 46 D) 48 Correct Answer : 42 Explanation :74088 = 2 * 2 * 2 * 3 * 3 * 3 * 7 * 7 * 7 = (2*2) * (3*3) * (7*7) * (2*3*7) Least number which should be multiplied to 74088 to make it a Perfect square = 2 * 3 * 7 = 42 Find the least number by which 175760 be devided to make it a perfect cube ? A) 10 B) 20 C) 100 D) 5 Correct Answer : 10 Explanation :175760 = 24 x 5 x 13 3 = 23 x 2 x 5 x 133 To make perfect cube, it must be divided by 2 x 5 = 10 √(248 + √(52+ √144)) = ? A) 14 B) 16 C) 16.6 D) 18.8 Correct Answer : 16 Explanation :√(248 + √(52 + √144)) => √(248 + √(52 + 12)) => √(248 + √64) => √(248 + 8) => √256 => 16 250 / √? = 10 A) 25 B) 250 C) 625 D) 2500 Correct Answer : 625 Explanation :Let 250 / √x = 10. Then √x= 250 / 10 = 25 Thus, x = 625 √(4/3) - √(3/4) = ? A) 1/2√3 B) - 1/2√3 C) 1 D) 2√3 Correct Answer : 1/2√3 Explanation :√(4/3) - √(3/4) = 2/√3 - √3/2 = (4 - 3)/2√3 = 1/2√3 If √2n = 64, then the value of n is ? A) 2 B) 4 C) 6 D) 12 Correct Answer : 12 Explanation :√2n = 64 ⇒ 2n/2 = 26 ⇒ n/2 = 6 ⇒ n = 12 (√5 - √3)/ (√5 + √3) is equal to ? A) 4 + √15 B) 4 - √15 C) 1/2 D) 1 Correct Answer : 4 - √15 Explanation :(√5 - √3)/ (√5 + √3) = (√5 - √3) / (√5 + √3) = (√5 - √3)2 / (5 - 3) = (5 + 3 - 2√5 x 3) / 2 = 2 (4 - √15) / 2 = (4 - √15) 3√(0.027/0.125) = ? A) 0.6 B) 0.3 C) 0.5 D) 0.2 Correct Answer : 0.6 Explanation :3√(27*1000/125*1000) => 3√(27/125) => 3√27 / 3√125 => 3√(33) / 3√(53) =>3/4 => 0.6 The largest three digit number which is a perfect cube is? A) 986 B) 729 C) 981 D) 864 Correct Answer : 729 Explanation :93 = 729 and 103 = 1000 So the required number = 729 3√(√ 729) = ? A) 9 B) 3 C) 8 D) 6 Correct Answer : 3 Explanation :3√(√ 729) = 3√(√ (272))= 3√27 => 3√(33) = 3 What is the smallest number by which 1400 be divided to make it a perfect cube? A) 130 B) 145 C) 160 D) 175 Correct Answer : 175 Explanation :1400 = 23 * 52 * 7 To make it a perfect cube, it must be divided by 52 *7 = 175 Find the least number by which 175760 be multiplied to make it a perfect cube? A) 100 B) 160 C) 80 D) 27 Correct Answer : 100 Explanation :175760 = 24 *5 *133 To make it a perfect cube it must be multiplied by 22 * 52 = 100. The cube root of 5.832 is ? A) 0.18 B) 0.28 C) 2.8 D) 1.8 Correct Answer : 1.8 Explanation :3√5.832 = 3√(5832/1000) =3√5832 / 3√1000 = 18/10 =1.8 The difference of squares of two consecutive odd numbers is always ? A) divisible by 8 B) divisible by 2 C) divisible by 16 D) divisible by 18 Correct Answer : divisible by 8 Explanation :Let two odd numbers be (2x + 1) and (2x + 3) Difference between the squares= (2x + 3)2 - (2x + 1)2 = (4x2 + 12x + 9) - (4x2 + 4x + 1) = 8x+8 = 8(x+1) which is always divisible by 8 Find the value of √ (0.25 * 2.25) ? A) 0.075 B) 0.705 C) 0.75 D) 7.500 Correct Answer : 0.75 Explanation :√ (0.25 * 2.25) =0.5*1.5 =0.75 (0.324 * 0.081 * 4.624) / (1.5625 * 0.0289 * 72.9 * 64) is the square root of ? A) 24 B) 2.4 C) 0.024 D) 1.2 Correct Answer : 0.024 Explanation :(0.324 * 0.081 * 4.624) / (1.5625 * 0.0289 * 72.9 * 64) =(324 * 81 * 4624) / (1.625 * 289 * 729 * 64) =9/15625 hence,the square root is √(9/15625) =3/125 =0.024