Question

Rita's water tank contains 7.8 gallons of water. Rita 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. Wendy will begin draining her water tank at a rate of 0.9 gallon per minute. After how many minutes will both water tanks contain the same amount of water? 25 min 30 min 35 min 75 min

Answer 1

30 minutes

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