# Maria's bathtub contains 60 gallons of water. She drains the tub at a rate of 12 gallons a minute. Write an equation to represent the number of gallons(g) remaining in the tub after(m)minutes. How...

Maria's bathtub contains 60 gallons of water. She drains the tub at a rate of 12 gallons a minute. Write an equation to represent the number of gallons(g) remaining in the tub after(m)minutes. How long will it take her to drain the tub at this rate?

jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted on

Volume of bath tub in gallons (V) = 60

Rate of draining water in gallons per minute (R) = 12

When time t = t min

Volume of water drained out in gallons = R*t

Volume of water drained out in gallons = 12t

Water retaining in bath tub = Total volume - volume drained

Water retaining in bath tub = V - Rt

Water retaining in bath tub = 60-12t

When the amount of water retaining in bathtub is 0 then the tub is fully drained.

60-12t = 0

t = 5

So bathtub will be fully drained in 5minutes.

Note:

Here we have to assume that the draining rate of bath tub remains constant at all time. Usually it decreases when the water volume decrease.

shgle | (Level 1) Honors

Posted on

60/12m if m is minute. So it will be drained in 5 minutes.

1 minute= 12 gallons 2 minutes= 24 gallons 3minutes=36 gallons

4 minutes=48 gallons 5 minutes= 60 gallons