Question

20 men can build 10m long wall in 30 days if 3 men leave and 8 men join how much time will be required to build the wall of 40m
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Answer 1

Answer:

So dealing with ratios.

Remember to find if the quantities are directly or indirectly proportional.

This one has three different variables related to each other.

20:1/10:1/30

More men means less days,Longer walls means more days.

first taking the ration of men to time 20:1/30

multiplying by 1/20 to take out 20 and then multiplying by 20 to replace by 25 so the factor required is 25/20=5/4

25:1/24

now ration for wall to time

1/10:1/24

dividing by 4

1/40:1/96

So the ration comes out to 25:1/40:1/96 hence days required is 96