Quick rates question (1 Viewer)

[mzkitkat]

Hello all...ive never been able to figure out these damn rates questions so id really appreciate some help here...

A tap fills up a tank in 5 minutes while another tap fills the same tank in 10 minutes. How long will it take to fill up if they are both on at the same time?

Thanks!

 

[pLuvia]

one minute it takes 1st tank to fill the tank to 2/10
one minute it takes 2nd tank to fill the tank to 1/10

Both working together

= (2/10+1/10)N=1
N=10/3 mins

More mathematical way
dq/dt=2/10
dp/dt=1/10
(dq/dt+dp/dt)=3/10
1/(3/10)=10/3

Edit: The reason for the 1 is to show that the tank is filled to 100% in N mins

Hope that helped