Correct Answer - Option 4 : 70
Concept
HCF : The greatest common divisor of two or more positive integers happens to be the largest positive integer that divides the numbers without leaving a remainder.
LCM : The Least common multiple or lowest common multiple, or smallest common multiple of two integers a and b, usually denoted by l.c.m.(a, b), is the smallest positive integer that is divisible by both a and b.
Co-prime : Two numbers are co-prime if they no common factor other than 1.
Formula used
Product of numbers = LCM × HCF
Calculation
HCF = 10
So, let the two numbers be 10a and 10b, where 'a' and 'b' are co-primes
LCM of two numbers = 120
⇒ 10a × 10b = LCM × HCF
⇒ 100 ab = 1200
⇒ ab = 12
Therefore, possible pairs of a and b could be
(3,4)
So, the numbers are (30, 40)
Hence, their sum is 70.