Multiple choice

$90$ men can complete a work in $24$ days working $8$ hours a day. How many men are required to complete the same working in $18$ days working $ 7\dfrac{1}{2} $ hours a day ?

  1. $112$ men
  2. $128$ men
  3. $140$ men
  4. $133$ men
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

M1*D1*H1 = M2*D2*H2. 90*24*8 = M2*18*7.5. 17280 = M2*135. M2 = 17280 / 135 = 128.

AI explanation

The total work equals 90 men times 24 days times 8 hours per day, which equals 17280 man-hours. The new daily work rate for one man is 7.5 hours, so the total man-hours required for 18 days of work by N men is N times 18 times 7.5. Setting 17280 equal to 135N gives N = 128, meaning 128 men are required.

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