Question 609311
zach can wash all the windows in his house in 3 hours.
 His brother COry can do the same job in 5 hours.
 How long will it take them to wash all the windows if they work together
:
Let t = time required, working together
Let the completed job = 1, (clean windows)
:
A typical shared work equation, each will do a fraction of the job, the two fractions add up 1
:
{{{t/3}}} + {{{t/5}}} = 1
multiply by 15 to clear the denominators
5t + 3t = 15
8t = 15
 t = 15/8
 t = 1.875 hrs working together
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