Multiple choice

30 men working together can build the concrete pavement for an entire city in 270 days. Due to unforeseen circumstances the work had to be stopped 30 days before it was over, and the contractor was given a time limit of 12 days to complete the rest of the work. How many more workers would the contractor have to employ to get the work done on time?

  1. 30

  2. 35

  3. 40

  4. 45

  5. 50
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The total work is 30 * 270 = 8100 man-days. After working for 240 days, 30 * 240 = 7200 man-days are completed, leaving 900 man-days. To finish in 12 days, the contractor needs 900 / 12 = 75 workers. Since 30 are already employed, 75 - 30 = 45 more are needed.

AI explanation

If 30 men can build the pavement in 270 days, the work requires 8100 man-days (30 x 270). If the work is stopped 30 days before completion, only 240 days of work was done by 30 men, yielding 7200 man-days. The remaining work is 8100 - 7200 = 900 man-days. To finish this in 12 days, 900 / 12 = 75 workers are needed. Therefore, the contractor must hire 75 - 30 = 45 more workers.

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