Question 874677
Here is a word problem that came up today 
:
It takes barry 4 hours to paint his house by himself when working alone.
 Christy can complete the job by herself in 11 hours.
 How long will it take them to complete the job if they work together?
:
Identify the variables
let t = time to complete the job when working together
:
let the completed job = 1
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Write a "shared work equation"
Each will do a fraction of the job, the two fractions add up to 1
:
{{{t/4}}} + {{{t/11}}} = 1
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Solve the equation
multiply by 44. cancel the denominators and you have:
11t + 4t = 44
15d = 44
t = 44/15
t = 2.9333 hrs; 2 + .933(60) = 2 hr 56 min
:
This means that both working will finish the job in 2.93 hrs which is 2 hr 56 min