The ratio of two numbers is 3:4 and their LCM is 120. The sum of numbers is:

 a) 70
 b) 35
 c) 40
 d) 105

SSC CHSL-2015

70. Solution Let the numbers be 3x and 4x. LCM of 3x and 4x = 12x Given that LCM of 3x and 4x is 12x => 12x = 120 => x = 120⁄12 = 10 Numbers are 30,40 Sum = 30 + 40 = 70