High School

Rita's water tank contains 7.8 gallons of water. She will begin filling her water tank at a rate of 2.1 gallons per minute. Wendy's water tank contains 97.8 gallons of water. She will begin draining her water tank at a rate of 0.9 gallons per minute.

After how many minutes will both water tanks contain the same amount of water?

A. 25 min
B. 30 min
C. 35 min
D. 75 min

Answer :

Answer:

30 minutes

Step-by-step explanation:

Given the following :

Rita's tank contains =7.8 gallons of water

Filling rate = 2.1 gallons per minute

Wendy's tank contains = 97.8 gallons

Drain rate =. 0.9 gallons per minute

After how many minutes will both contain the same amount of water.

Let number of minutes = m

Rita is filling :

Initial + increase

7.8 + 2.1m ----(1)

Wendy is emptying:

Initial - decrease

97.8 - 0.9m - - - (2)

Equate both ;

(1) = (2)

7.8 + 2.1m = 97.8 - 0.9m

2.1m + 0.9m = 97.8 - 7.8

3m = 90

m = 90 / 3

m = 30 minutes

Other Questions