Question

A water tank holds 630 gallons but is leaking at a rate of 4 gallons per week. A second water tank holds 840 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

Answer: The answer is 70 weeks.

Step-by-step explanation:

Let, after t weeks the amount of water in the two tanks be the same.

Given, a water tank holds 630 gallons but is leaking at a rate of 4 gallons per week.

Then, the amount of the water in this tank after t weeks = 630-4t gallons.

Again, and a second water tank holds 840 gallons but is leaking at a rate of 7 gallons per week.

Then, the amount of the water in this tank after t weeks = 840-7t gallons.

Now, by the given condition

630-4t = 840-7t

⇒ 7t-4t = 840-630

⇒ 3t = 210

⇒ t = 70

∴The required time is 70 weeks.