Multiple choice

A alone can complete a work in 45 days. He worked for 5 days and then B joined him. Now remaining work is completed in 24 days. Find the total number of days in which B alone will complete the whole work.

  1. 52.5 Days

  2. 67.5 Days

  3. 62.5 Days

  4. 75 Days

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

A completes 1/45 of work per day. In 5 days, A does 5/45 = 1/9 of work. Remaining work = 8/9, completed by A+B in 24 days, so (1/45 + 1/B) × 24 = 8/9. Solving: 1/45 + 1/B = 1/27. Thus 1/B = 1/27 - 1/45 = (5-3)/135 = 2/135, so B = 67.5 days alone.

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