Question

One crew can seal a parking lot in 14 hours and another in 18 hours. How longwill it take to seal the parking lot if the two crews work together?

Answer 1

Let the amount of work be L.

Therefore, the rate of work of the first team:

`(L)/(14)`

Similarly, the work rate of the second team is:

`(L)/(18)`

Therefore, the combined rate of both crews is given by:

`(L)/(14)+(L)/(18)=(8L)/(63)`

The time is given by:

`\text{ time }=\frac{\text{ amount of work}}{\text{ rate}}`

Therefore,

`\text{ time }=L/(8L)/(63)=L*(63)/(8L)=(63)/(8)=7hours\text{ }53\text{ min}`

Hence, the required time is 7 hours 53 minutes

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