Question

A water tank holds 621 gallons but is leaking at a rate of 4 gallons per week. A second water tank holds 828 gallons but is leaking at a rate of 7 gallons per week. After how many weeks will the amount of water in the two tanks be the same?

Answer 1

69 weeks

Explanation:

Let the number of weeks be x.

The first tank holds 621 gallons is leaking at a rate of 4 gallons per week. This means that after x weeks, the amount of water in the tank is:

621 - 4x

The second tank holds 828 gallons is leaking at a rate of 7 gallons per week. This means that after x weeks, the amount of water in the tank is:

828 - 7x

After a certain amount of weeks, the amount of water in both tanks is the same. That means that:

621 - 4x = 828 - 7x

=> 7x - 4x = 828 - 621

3x = 207

x = 207 / 3 = 69

This means that the amount of water in the tank will be the same after 69 weeks.