After pulling the plug from a tub the amount of water in the

After pulling the plug from a tub, the amount of water in the tub changed at a constant rate of - 1.5 gallons per minute. After draining for 3.1 minutes, there were 36 gallons of water remaining in the tub. Find the change in the number of gallons in the tub when the number of minutes the tub has been draining changes from 0 minutes to 5 minutes. - 5.4 Preview How many gallons of water were in the tub before the tub began to drain? 12 Preview Write a formula that determines the number of gallons in the tub, y, in terms of the number of minutes elapsed since the plug was pulled, x. Preview

Solution

rate of change =-1.5 gallons per minute

a)from 0 to 5 minute time change =5-0 =5 minutes

change in number of gallons =rate of change *time

change in number of gallons =-1.5*5

change in number of gallons =-7.5 gallons

b) number of gallons in tub =(-1.5)(0-3.1) +36

=4.65+36

=40.65 gallons

c)number of gallons in tub

y =40.65-1.5x