1.  If the sum of two numbers is 55 and the H.C.F. and L.C.M. of these numbers are 5 and 120 respectively, then the sum of the reciprocals of the numbers is equal to:
A. 55/601
B. 601/55
C. 11/120
D. 120/11

Answer: Option C

Explanation:

Let the numbers be a and b.

Then, a + b = 55 and ab = 5 x 120 = 600.

The required sum 

1 + 1 = a + b = 55 = 11
a b ab 600 120