Explanation:
A swimming pool contains 2,500 gallons of water. Roger fills the swimming pool at 5 gallons per minute. Another swimming pool contains 5,200 gallons of water. Maria drains the swimming pool at 15 gallons per minute. After how many minutes will the two swimming pools contain the same amount of water?
2,500 + 5m = 5,200 - 15m
2,500 + 5m = 5,200 - 15m
add 15m to both sides:
2,500 + 5m + 15m = 5,200 - 15m + 15m
2,500 + 20m = 5,200
subtract 2,500 from both sides:
2,500 + 20m - 2,500 = 5,200 - 2,500
20m = 2,700
divide both sides by 20:
20m/20 = 2,700/20
m = 135