Question

A tank contains 4L of water at first. Tap A is turned on and water from tap A flows into the container at the rate of 8L per minute. After 3 minutes, Tap B is turned on. Both taps are turned off together after another 5 minutes. If the total amount of water in the container is 77L after both taps are turned off, what is the rate of the water flowing from Tap B?

Answer 1

A's rate --- 8 L/min
B's rare --- x+8 L/min

combined rate = (x+8) L/min
for first 3 minutes, amount of water = 24 L
next 5 minutes, amount of water = 5(x+8) or 5x+40 L

so , 4 + 24 + 4x+40 = 77
4x = 9
x = 9/4 L/min or 2.25 L/min

B's rate is 2.25 L/min

Answer 2

B's rate ---- x L/min