Question

what was the initial amount of water in a barrel, in liters, if x liters remain after y liters were spilled and 6 were added?

Answer 1

Let's call A the initial amount of water, in liters, in that barrel.

After y liters were spilled, the amount left was

A - y

Then, after 6 liters were added, the final remaining amount was given by:

A - y + 6

Now, since x liters remain, we have:

x = A - y + 6

Therefore, if we can find the expression for the initial amount of water, in liters, by isolating A in that equation:

x = A - y + 6

x + y = A + 6

x + y - 6 = A

A = x + y - 6

Thus, the initial amount of water was (x + y - 6) liters.