A tank filled with two pipes. First pipe alone could fill the tank in 24mintes and the second pipe alone, in 30 minutes.How many minutes will be required to fill the tank if both pipes are open?
<<<<<<<<<<<THIS IS AN ATTEMPT AND IN NO WAY DO I KNOW I AM CORRECT>>>>>>>>>>>>>>>
Lets make tanks a unit, and call 1 tank 1T
Pipe A fills 1T every 24 minutes, so it fills at a rate of 1/1440 T every second
Pipe B fills 1T every 30 minutes, so it fills at a rate of 1/800 T every second
Therefore both combined fill at a rate of 7/3600 T each second
Therefore to fill an amount T, 3600/7 seconds are needed = 60/7 minutes = 8.57 minutes
So to the nearest minute it should take 9 minutes. I'm not sure how accurate it needed it, or how old you are, or if I made a mistake, so please check the other answers as well. I made up the method on the spot, but I hope it helps!
Comments
First pipe ALONE = 24 minutes
Second pipe ALONE = 30 minutes
First pipe ALONE in 1 MINUTE = 1/24 of the tank
Second pipe ALONE in 1 MINUTE = 1/30 of the tank
TOGETHER in 1 MINUTE = 1/24 +1/30 = 54/720 = 9/120 = 3/40 of the tank
TOGETHER they will FILL THE TANK in 40/3 minutes or
13.33 minutes OR 13 minutes 20 seconds ANSWER
<<<<<<<<<<<THIS IS AN ATTEMPT AND IN NO WAY DO I KNOW I AM CORRECT>>>>>>>>>>>>>>>
Lets make tanks a unit, and call 1 tank 1T
Pipe A fills 1T every 24 minutes, so it fills at a rate of 1/1440 T every second
Pipe B fills 1T every 30 minutes, so it fills at a rate of 1/800 T every second
Therefore both combined fill at a rate of 7/3600 T each second
Therefore to fill an amount T, 3600/7 seconds are needed = 60/7 minutes = 8.57 minutes
So to the nearest minute it should take 9 minutes. I'm not sure how accurate it needed it, or how old you are, or if I made a mistake, so please check the other answers as well. I made up the method on the spot, but I hope it helps!