Rani can complete a stitching order in 24 days. After working for 6 days, her sister joins her, and they finish it in 10 more days.
In how many days can her sister alone complete the work?
Show answer & explanation
Correct answer: A
Explanation
Rani's rate = 1/24
Work done in 6 days = 6/24 = 1/4
Remaining work = 1 − 1/4 = 3/4
Their combined rate = (3/4) / 10 = 3/40
Sister's rate = 3/40 − 1/24
= (9 − 5) / 120 = 4/120 = 1/30
Sister's time = 30 days