Question 648334
1/7+1/4=1/X Find a common denominator (7*4=28)
4/28+7/28=1/x
11/28=1/x Cross multiply
11x=28*1
11x=28
x=28/11
x=2.55 Hours when they work together.
Proof:
1/7+1/4=1/2.55
.143+.25=.392
.393=.392