Question 1196717
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The response from the other tutor shows a standard formal algebraic method for solving this kind of "working together" problem.<br>
Here is an alternative method that many students like.<br>
(1) Consider the least common multiple of the two given times: LCM(10,18) = 90.
(2) Determine the number of houses that could be painted in 90 hours:
Craig alone: 90/18 = 5 houses
Craig and John together: 90/10 = 9 houses
(3) The difference of 4 houses in 90 hours is the amount of work John could do alone.<br>
John could paint 4 houses in 90 hours, so the number of hours it would take him to paint the one house alone is 90/4 = 22.5.<br>
ANSWER: 22.5 hours<br>