rate of new pump = 1/5 tanks/hr
rate of old pump = 1/7 tanks/h
combined rate = 1/5 + 1/7 tanks/hr
= 12/35 tanks/hr
time to fill 1 tank with both pumps = 1 tank/(12/35) tanks/hr
= 35/12 hours
= 2 hours and 55 minutes
Q work crew has two pumps, one new and one old. The new pump can fill a tank in 5 hours. The ols pump can fill the same tank in 7 hours.
a. How much of a tank can be filled in 1 hour with the new pump? with the old pump?
b.Write an expression for the number of tanks the new pump can fill in
(t) hours.
c. Write an expression for the number of tanks the old pump can fill in (t) hours.
d. Write and solve an equation for the time it will take th epumps to fill one tank if the pumps are used together.
1 answer
2 answers