Multiple choice

P can complete a work in 21 days while Q is 25% less efficient than P. Q worked for 7 days and left , remaining work is completed by R in 27 days. Find in how many days R can complete the whole work alone ?

  1. 27 days

  2. 36 days

  3. 32 days

  4. 40 days

  5. None of These
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

P's efficiency = 1/21 work per day. Q is 25% less efficient, so Q's efficiency = 0.75 × 1/21 = 3/84 = 1/28. Q worked for 7 days: 7/28 = 1/4 work done. Remaining work = 3/4, completed by R in 27 days. R's rate = (3/4)/27 = 1/36. So R alone takes 36 days.

Keep practicing — related questions