Working together Jill and Bill can tar a roof in 6.67 hours. Had he done it alone it would have taken Bill 15 hours how long would it take Hill to do alone?

Question

Mathematics

Guest

8 December, 02:08

Working together Jill and Bill can tar a roof in 6.67 hours. Had he done it alone it would have taken Bill 15 hours how long would it take Hill to do alone?

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Answers (1)

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Celeste Bowen · Answer 1

Found a simple equation.

h = (a * b) / (a + b)

h = total hrs with both.

a = total hrs Bill.

b = total hrs Jill.

6.67 = (15 * b) / (15 + b)

6.67 (15 + b) = 15b

100.05 + 6.67b = 15b

100.05 = 8.33b

b = 10005 / 833 or 12.0108 hrs