If a tank fills in 4hours and empties in 6hours how long does it take if the tank is emptying and filling at the same time, how long will it take to be filled? this is all the info the problem has if you can figure it out ill give 100 points and the thing: )

12 hours.

Step-by-step explanation:

In 1 hour if the tap filling the tank runs on its own it will fill 1/4 of the tank. But if the tap that empties the tank is run at the same time it empties 1/6 of the tank. So the net result in 1 hour is that 1/4 - 1/6 = 1/12 of the tank is filled.

In the next hour the same thing happens - another 1/12 is filled.

So the tank will be filled in 12 hours.

Every hour, the tank would fill 1/4 of the way, but it would be set back by 1/6 of it's original progress due to the emptying. So how much progress did it actually make in that hour? 1/4 - 1/6 = 0.08333333. It filled 0.0833...%

This would mean '1' = 100%, so we have the equation 0.0833... x ? = 1

Well, 0.083333 is equal to the fraction 1/12. Also, 0.083333 x 12 equals 1. You can take either of those two routes to find your answer, but we can tell either way that it takes 12 hours.

Answer is 14, look below for explanation.

Step-by-step explanation:

Andrew has 17 albums and John has 6 albums that are not in Andrew's.

They have 9 of the same albums.

The ones that Andrew ONLY has: 8

the ones that Andrew shares with John: 9

The one that John has alone: 6

the answer is 8+6 = 14