Question

Two numbers differ by 10. If their LCM is 120 and HCF is 10, then the sum of the numbers is:  

Options

• 120

• 130

• 50

• 70

Answer 1

70

Explanation:

From the formula,

H.C.F × L.C.M = product of numbers.

Let two numbers be a and b.

Now, a − b = 10

So, a + b = `sqrt(("a" - "b")^2 + 4"ab")`

= `sqrt((10)^2 + 4 xx 1200)`

⇒ a + b = `sqrt(100 + 4800)`

= `sqrt4900`

= 70

∴ Sum of two numbers = 70