LCM of two numbers is 28 times their HCF. The sum of HCF and LCM is 1740. If one of these numbers is 240, the sum of digits of the other number is -

A) 2

B) 5

C) 6

D) 8

 LCM = 28 HCF

HCF + LCM = 1740

HCF + 28HCF = 1740

29HCF = 1740

HCF = 60

LCM = 1680

HCF * LCM = Product of numbers

60 * 1680 = 240 * x

x = 60 * 1680 / 240

x = 1680 / 4 = 420

Sum of digits =  4  + 2 + 0 = 6

Ans: C) 6