1. If 8 workers can finish a job in 6 hours, how many workers will it take to finish the same job in 4 hours?
Answers
Step 1: Make two columns workers and hours. Write worker values under workers column and hour values under hours column and denote hours to be found with x.
Step 2: Find relationship between two columns by checking the fact that if number of workers decrease from 8 to 4, certainly they would require more hours x to get the job done. So the relationship between both columns is inverse.
Step 3: Form equation keeping relationship in mind.
a) If you divide 8 by 4 then being inverse relationship, you must divide x by 6, so that equation becomes:
8/4 = x/6
Now cross multiply,
4x = 8*6
x = 8*6/4
x = 12
b) If you divide 4 by 8 then being inverse relationship, you must divide 6 by x, so that equation becomes:
4/8 = 6/x
Now cross multiply,
4x = 8*6
x = 8*6/4
x = 12
So you see that finding relationship (step 2) between columns would help you solve such questions easily in future.
If there were direct relationship between columns then the equations would go like this:
8/4 = 6/x
OR
4/8 = x/6
Given:
Total number of workers = 8
Number of hours taken to finish a job = 6
To Find:
How many workers will complete the same job in 4 hours ?
Solution:
Let the workers be = x
Total work = 8 × 6 = 48
Thus, as per question -
= x × 4 = 48
= 4x = 48
= x = 48/4
= 12
Answer: The workers needed to complete the job in 4 hours are 12.