If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working for 8 hours a day do the same piece of work?
Less man, more days
More Man, less days
For 20 men working 7 hors a day , number of man hours = 20×7=140
For 15 men working 8 hors a day , number of man hours =15×8=120
Given 20 men finishes work in 10 days, let 15 men takes x days
Therefore,
Man Working Hours :: Time taken
20 7 10
15 8 x