Multiple choice

12 men, working 9 hours per day can build a wall 30 mts long in 20 days. In how many days will 18 men working 8 hours a day, build a wall of length 20 mts?

  1. 15

  2. 10

  3. 25

  4. 30
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Use the formula (M1*D1*H1)/W1 = (M2*D2*H2)/W2. (12*20*9)/30 = (18*D2*8)/20. 2160/30 = 144*D2/20. 72 = 7.2*D2, so D2 = 10.

AI explanation

Using the work equivalence formula M1 times D1 times H1 divided by W1 equals M2 times D2 times H2 divided by W2, we substitute the given values. This sets up the equation (12 times 20 times 9) divided by 30 equal to (18 times the required days times 8) divided by 20. Solving for the required days gives 72 divided by 18, which means it will take 10 days to build the wall.

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