Question

Working together, jack and Ming can tar a roof in 6.16 hours. Had she done it alone it would have taken Ming 11 hours. Find how long it would take jack to do it alone

Answer 1

14 hours

Explanation:

Jack and Ming can togrther tar a roof in 6.16 hours.

In 1 hour they can tar 1/6.16 of the roof.

Ming alone can tar the roof in 11 hours.

So in 1 hour he can tar 1/11 of the roof.

Let the number of hours taken by Jack to tar the roof = x

Then in 1 hour Jack can tar 1/x of the roof.

=>
`\[(1)/(x)+(1)/(11)=(1)/(6.16)\]`

=>
`\[(1)/(x)=(4.4)/(61.6)\]`

=> x=14

Jack will take 14 hours to tar the roof alone.