Pump a can fill a tank of water in 5 hours. pump b can fill the same tank in 8 hours. how long does it take the two pumps working together to fill the tank? (round your answer to the nearest minute).

185 min

Step-by-step explanation:

Data

Pump a    = Pa

Pump b    = Pb

Full Tank  = Ft

Tank          = T

we have that Pa fills T in 5 hours and Pb fills the same tank in 8 hours, we must find that T capacity is filled in one hour by Pa and Pb

if Pa fills T in 5h, in 1h what capacity is filled, ; if Pb fills T in 8h, in 1h what capacity is filled, , and now we must find:

How long will Pa and Pa be used together to fill T

. ; The capacity of T = 40/40, so if Pa+Pa in 1h fill then to fill 40/40 in h=?

, but h must be in min so