Question

Susan is filling two ponds in her back yard. She has to dig the hole, put the liner in, and fill the pond. The first pond holds 75 gallons of water and is filling at a rate of 7 gallons of water per hour. The second holds 115 gallons of water and is filling at a rate of 3 gallons of water per hour. Write an equation for each tank that represents the total amount of water in gallons in the tank, y, in terms of the number of hours, x, that the tanks are draining

Answer 1

I suspect you meant that they are draining. So, the two equations would be

y = 75-7x
and
y = 115-3x

for suitable domains of x.