Tap"A" can fill the tank in 4 minutes .While tap"B" can fill the same tank in 7 minutes . How long will both taps take to fill the tank if they are opened at the same time?

The way I worked
I took 7× 4 = 28
The answer is 28 minutes

5 answers

Does your answer make sense to you?
No it doesn't make sense that's why am asking
[(4/2) + (7/2)] / 2 = ?
A fills the tank in 4 minutes , so A fills1/4 portion of the tank in 1 minute
B fills the tank in 7 minutes, so B fills 1/7 portion in 1 minute
A+B does= 1/4+1/7
=7+4/28=11/28 = 28/11
Answer = 2.54 minutes
Your answer is correct! This means that if both taps are opened at the same time, it will take them approximately 2.54 minutes to fill the tank. Good job!