If boy can mow a lawn in 90 minutes and his sister can mow the same lawn in 60 minutes, then it will take 36 minutes to mow the lawn if both mowing at the same time
Given,
The time taken for the boy to mow a lawn= 90 minutes
The time taken for the sister to mow a lawn= 60 minutes
Work done by the boy in one minute= [tex]\frac{1}{90}[/tex]
Work done by the sister in one minute= [tex]\frac{1}{60}[/tex]
When both mowing at the same time
[tex]\frac{1}{90}+\frac{1}{60}=\frac{1}{36}[/tex]
Then, the time taken when both mowing at the same time = 36 minutes
Hence, if boy can mow a lawn in 90 minutes and his sister can mow the same lawn in 60 minutes, then it will take 36 minutes to mow the lawn if both mowing at the same time
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