Question 1194895
Noni can paint his garage in 3 1⁄2 hours while his friend Anton can paint it in 4 hours. If they work together, if they started at 4:00 P.M. at what time they will finish the said job?
<pre>Let time they take, working together, be T
Then Noni's and Anton's per-hour rates are: {{{matrix(1,3, 1/3.5, and, 1/4)}}}, respectively
We then get: {{{matrix(1,3, 1/3.5 + 1/4, "=", 1/T)}}}
           4T + 3.5T = 14 ------ Multiplying by LCD, 4T(3.5)
                7.5T = 14
Working together, time both will take to complete job, or {{{matrix(1,13, T, "=", 14/7.5, "=", 28/15, "=", 1&13/15, "hours,", or, 1, "hour,", 52, minutes)}}}
Time when both will finish job: {{{highlight_green(matrix(1,7, 4:00, "p.m.", "+", "1:52", "=", 5:52, "p.m."))}}}