1. 

The H.C.F. of 9 , 12 , 18 and 21 is:
10 25 35 40

A. 3/5
B. 252/5
C. 3/1400
D. 63/700

Answer: Option C

Explanation:

Required H.C.F. :

= H.C.F. of 9, 12, 18, 21 = 3
L.C.M. of 10, 25, 35, 40 1400