Multiple choice

A contractor agrees to complete a work in 24 days. He employs 18 workers initially. After 8 days, he realizes that only 25% of the work has been completed. How many additional workers are required to complete the remaining work on time, assuming all workers work at the same rate?

  1. 18

  2. 24

  3. 9

  4. 12

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

Work done = 25% in 8 days with 18 workers. Remaining work = 75% in 16 days (24-8). Let X be total workers needed. (18 * 8) / 0.25 = (X * 16) / 0.75. 144 / 0.25 = 16X / 0.75. 576 = 21.33X. Or simply: 18 workers do 25% in 8 days. To do 75% in 16 days, we need (18 * 3) / 2 = 27 workers. Additional workers = 27 - 18 = 9.

AI explanation

Since 18 workers complete 25 percent of the work in 8 days, they would complete the full work in 32 days, meaning the total work requires 18 multiplied by 32, which is 576 man-days. The work already completed is 576 multiplied by 0.25, which is 144 man-days, leaving 432 man-days of work to be done. To finish the remaining 432 man-days in the remaining 16 days, the contractor needs 432 divided by 16, which is 27 workers. Since he already has 18 workers, he requires 27 minus 18, which is 9 additional workers.

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