Question

The L.C.M of two numbers is 120 and their H.C.F. is 10. Which of the following can be the sum of those two numbers?

• A. 140
• B. 80
• C. 60
• D. 70
• E. 224

Answer 1

The correct option is D 70

Let the number be 10x and 10y, respectively and x and y are prime to each other.
Therefore, $L.C.M.=10xy$
$\Rightarrow 10xy=120\Rightarrow xy=\frac{120}{10}=12$
Possible pairs = (3,4) or (1,12)
Hence, sum of the numbers $=30+40=70$