A and B together do a piece of work in 10 days. B alone does it in 15 days. How long will A take alone?
Show answer & explanation
Correct answer: C
Explanation
Given:
A + B's time = 10 days
B's time = 15 days
By formula:
Work rate = 1 / time
A + B's rate = 1/10
B's rate = 1/15
A's rate = 1/10 − 1/15
= (3 − 2) / 30
= 1/30
A's time = 30 days