Rahul alone can complete a work in 10 days and Sonu alone can complete the same work in 15 days. If they work together for 4 days, then what part of total work is left?
A.1/5
B.1/3✓ Correct
C.2/5
D.2/3
Explanation
Rahul's rate = 1/10 per day; Sonu's rate = 1/15 per day. Combined rate = 1/10+1/15 = 1/6 per day. Work done in 4 days = 4/6 = 2/3. Work remaining = 1 – 2/3 = 1/3.
💡 Practice unlimited SSC CHSL PYQs + AI-tracked progress on each topic. Sign up free →