250 men can finish a work in 20 days working 5 hours a day. To finish the work within 10 days working 8 hours a day, the minimum number of men required is ______?

300

310

312

313

Let's calculate the total work hours:

250 men * 20 days * 5 hours/day = 25,000 man-hours

To finish the work in 10 days working 8 hours a day:

Let x be the number of men required:

x men * 10 days * 8 hours/day = 25,000 man-hours (to complete the same amount of work)

x * 80 = 25,000

x = 25,000 / 80

x = 312.5 (313)