If A&B work together they will finish the job in 2 hours and 48 minutes. If they work independently; A will finish the job 4 hours and 12 minutes before B. The challenge is to find both their individual rate/speed for finishing the job if they work independently. Just to clarify (my English might a little un-clear), the A will do the job in X hours if he works alone; and B will finish the job in Y hours if he does it only by himself. ^^

Cheers & kudo for anyone who can solve this problem (and of course explain to me =)

Here's how to think it through - use the analogy of distance = rate time time. Suppose the job is to travel distance D. For worker A who takes time T_a to do his job his velocity is:


And for worker B you have



When they work together the time required is



Note that for all three equations D is a constant - it's the size of the job and is the same for both workers. When they work together their combined velocity is



So you have:



For your problem you've been given and the value for . So you can now solve for and . Post back and show us what you get for an answer.

its saying that if they work together they would finish faster if they work independently it would take them 2 hours more.so worker b you have Vb = D-T b
for a you have D-T a.so Va+Vb= . D v total