A does 20% less work than B. If A can complete a piece of work in $${\text{7}}\frac{1}{2}$$ hours, then B can do it in ?

A. 5 hours

B. 4 hours

C. 6 hours

D. 7 hours

Answer: Option C

Solution(By Examveda Team)

Ratio of times taken by A and B
$$\eqalign{ & = 100:80 \cr & = 5:4 \cr} $$
Suppose B takes x hours to do the work
$$\eqalign{ & \Rightarrow 5:4::\frac{{15}}{2}:x \cr & \Rightarrow x = \left( {\frac{{4 \times 15}}{{2 \times 5}}} \right) \cr & \Rightarrow x = 6{\text{ hours}}{\text{}} \cr} $$