Question

Elsa's fish tank has 17 liters of water in it. She plans to add 6 liters per minute until the tank has more than 77 liters. What are the possible numbers of minutes Elsa could add water?

Answer 1

At least 10 minutes.

Explanation:

We gotta make a little equation for this one! Elsa wants the tank to hold at least 77 liters. It has 17 liters in it already and is filling at a rate of 6 liters per minute. This can be expressed with the equation 77 = 17 + 6x.

Now we solve. First step is to subtract seventeen from each side. The equation now looks like 60 = 6x.

Step two is to divide both sides by six to get x by itself. 60/6 is 10, so x = 10.

In English, this means that Elsa has to fill the fish tank for at least 10 minutes for there to be 77 liters of water in it. Be very careful to include "at least ten minutes", otherwise the answer could be counted wrong.