Question 1077702
Time for A to do 1 job, x.


Time for B to do 1 job, x-1.


Time for C to do 1 job, x+2.


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Workman A and B tegether:
{{{1/x+1/(x-1)=1&12/60}}}
Solve this for x, and then evaluate the one-job times for B and C.