Problem Solving

P works 25% more efficiently than Q and Q works 50% more efficiently than R. To complete a certain project , P alone takes 50 days less than Q alone. If, in this project P alone works for 60 days and then Q alone works for 125 days, in how many days can R alone complete the remaining work?

A. 50 days
B. 75 days
C. 100 days
D. 150 days
E. 80 days

The OA is B.

I'm confused with this PS question. Experts, any suggestion about how to solve it? Thanks in advance.