Question 107495
let x be the number of hours it takes Sarah to do the job
let y be the number of hours it takes Dick to do the job
:
so sarah can do 1/x of the job per hour
and Dick can do 1/y of the job per hour
:
{{{((1/x)+(1/y))2=1}}}
:
{{{(1/5)+(1/y))2=1}}}
:
{{{(2/5)+(2/y)=1}}}
:
{{{2/y=3/5}}}
:
{{{3y=10}}}
:
{{{y=10/3}}}hours or 3 and 1/3 hours(time it takes Dick to do job by himself