SOLUTION: - One tractor can plow a field in 8 hours and another in 10 hours. In how many hours can both tractors plow the field together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: - One tractor can plow a field in 8 hours and another in 10 hours. In how many hours can both tractors plow the field together?       Log On


   

Question 907742: - One tractor can plow a field in 8 hours and another in 10 hours. In how many hours can both tractors plow the field together?


Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
1/a+1/b=1/x
1/8+1/10=1/x
10/80+8/80=1/x
18/80=1/x
x=80/18
x=4.44444444 hours working together
check
x/a+x/b=1
x/8+x/10=1
4.44444444/8+4.44444444/10=1
0.55555556+0.44444444=1
1.0=1
ok