at a time A,do 20% less work than B.if A do any work in 15/2 hour,then in how many hour B will finish work?  Pick one.
A) 5 hour  B) 11 / 2 hour  C) 6 hour  D) 13 / 2 hour  E) 8 hour

Rationale: let b will finish a work in x hour . then , in x hour a , 80 / 100 = 4 / 5 work do ratio of work done by a and b = inverse ratio of time taken 4 / 5 : 1 = 2 / 15 : 1 / x 4 / 5 * 1 / x = 1 * 2 / 15 = 4 / 5 x = 2 / 15 ; x = 6 . time = 6 hour answer c
Answer: C