Question

There are 3 inlet taps and 1 outlet tap with diameters 8, 6, 2 (cms – inlet taps) and 4 cm respectively. The rate of flow of oil is directly proportional to the square of the radius of the tap. It takes 9 minutes for the smallest tap to fill an empty tank. What is the time taken to fill an empty tank when all the taps (inlet + outlet) are kept open?

Answer 1

the answer is similar to this
http://wiki.answers.com/Q/How_much_time_is_required_to_fill_a_tank_if_pipe_A_can_fill_it_in_20_minutes_pipe_B_can_fill_it_in_30_minutes_and_pipe_C_can_drain_it_in_40_minutes_and_all_of_the_pipes_are_opened_on_an_empty_tank

Answer 2

shoot i just answered this and lost it somehow!! i've no time to type it now = the answer i got was 9/22 minutes

Answer 3

scroll down for related answers in the link I provided. You should get an idea as to how to approach this problem

Answer 4

could you help how to calcuate the rate of flow

Answer 5

rate of flow is proportional to radius squared
so flow rate of tap A = k*8^2 = 64k
similarly the flow rates of the other three are 36k, 4k and 16k

Answer 6

Hi, but shouldn't the radius be 4, since diameter is 8

Answer 7

oh you are right. well spotted.
so it is 16k, 9k, k and 4k

Answer 8

getting the answer as 18/22, but it seems to be 7/22

Answer 9

total flow = 26-4= 22

Answer 10

hi

Answer 11

total flow rate is 22k per minute. so what is the next step?
what is the value of k?

Answer 12

total capacity of the tank is 36 units (2^2*4.5)

Answer 13

total flow that comes is 16+9+1-4==22

Answer 14

ok got it, total 9 units, 9/22

Answer 15

thanks for your help

Answer 16

np. glad you could work it out on your own.