Multiple choice

A is thrice as good a work man as B and takes 60 days less than B for doing a job. The time in which they can do it together is?

  1. 15 days

  2. 60 days

  3. 22.5 days

  4. 28 days

  5. 25 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let B take x days, then A takes x/3 days. Given x - x/3 = 60, so 2x/3 = 60, x = 90. B takes 90 days and A takes 30 days. Together they take (90 * 30) / (90 + 30) = 2700 / 120 = 22.5 days.

AI explanation

Let B take X days to complete the job, so A takes (X minus 60) days. Because A is thrice as efficient, 3 multiplied by (X minus 60) equals X, which solves to X equals 90 days for B. Their combined daily work is 1 divided by 30 plus 1 divided by 90, equaling 4 divided by 90, so they complete the job together in 22.5 days.

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