I can not get how to form a formula or equation for this question. I don't want the answer I just need help getting it started. Thanks

Jim can mow Mr.Smith's lawn in 6 hours, Bob can mow Mr.Smith's lawn in 4 hours. How long would it take them to mow the yard if they worked together?

Jim can mow Mr.Smith's lawn in 6 hours, Bob can mow Mr.Smith's lawn in 4 hours. How long would it take them to mow the yard if they worked together?

Just to get you started:

Jim can do 1/6 of the job per hour, Bob can do 1/4 of the job per hour. So together they can do 1/6 + 1/4 of the job per hour.

Is that enough of a hint?

I think reinsuranc has the best method to do the problem... I guess if you want to state the solution more algebraically, we could say:

1/4 x +1/6 x = 1

where x is the number of hours needed for them to finish the job together. If there are others working on it, tack on the extra members' contributions.