Question 291479
Let j=number of hrs it takes jerry to do the job.
in one hr jerry can do 1/j of the job and and tom can do 1/(j-2)
1/j + 1/(j-2)=1/4 in one hour
4(j-2)+4j=j(j-2)
4j-8+4j=j^2-2j
j^2-10j+8=0 see below
j=9.12... hrs
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Ed
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 *[invoke quadratic "x", 1, -10, 8]