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

Levine

Mathematics

30 May, 15:00

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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Melina Quinn · 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