R alone can complete a work in 32 days. S alone can complete the same work in 40 days. They work together for 8 days. What part of total work is completed?
Show answer & explanation
Correct answer: C
Explanation
Work done by R in 1 day = 1/32
Work done by S in 1 day = 1/40
Total work done in one day = 1/32 + 1/40
= 5/160 + 4/160
= 9/160
Work done in 8 days = 8 × 9/160
= 72/160 = 9/20