Maria's fish tank has 16 liters of water in it. She plans to add 4 liters per minute until the tank has more than 64 liters. What are the possible numbers of minutes Maria could add water?

Answer 1

Without all the algebra: you need to add at least 64 - 16 = 48 liters.

At the rate of 1L every 4 min. that would take 48/4 = 12 min. So anything more than 12 min would result in more than 64 L in the tank.

Answer 2

What do you know?

Tank Capacity = 64 L

Liters tank already has = 16 L

How much you're adding = 4L per 1 minute (4L / 1m)

The number of minutes = x

The math equation is:

(Total Tank Capacity) < (Water tank already has) + (How much you're adding per minute) x (the number of minutes)

64L < 16L + (4L) * x (mins)

64L - 16L < (4L) * x (mins)

48L < 4L * x

48/4 < x

12 < x

Therefore, x > 12, meaning it will take more than 12 minutes to fill the take up more than 64L

Answer 3

Set up an inequality to get started, where x is the amount of minutes you wish to add water:

64 < 16 + 4x

Then solve for x:

64 - 16 < 16 - 16 + 4x

48 < 4x

divide both sides by 4

x > 12

Mariah must add 4 gallons of water per minute for over 12 minutes.