pre-Algebra

Question

A tank that was filled with 80 liters of water is leaking, losing 3 liters of water a day. Another tank that was filled with 60 liters of water on the same day is also leaking, losing 1 liter of water a day. After how many days will the number of liters of water be the same in both tanks?

Answer 1

y = -3x + 80

y = -x + 60

 

To solve this, we set the equations equal to one another:

-3x + 80 = y = -x + 60

-3x + 80 = -x + 60

To isolate x, we start by adding 3x to both sides:

80 = 2x + 60

subtract 60 from both sides:

20 = 2x

Divide by 2

10 = x

It will take 10 days

 

check:

y = -3 * 10 + 80

y = -30 + 80

y = 50

 

y = -10 + 60

y = 50