Beverage Dispenser C and Beverage Dispenser D have a total amount of 2799 mℓ of water. For Beverage Dispenser D and Beverage Dispenser E, the total amount of water is 4083 mℓ. The amount of water in Beverage Dispenser C is ³₇ the amount of water in Beverage Dispenser E. What is the average amount of water in the 3 beverage dispensers?
Beverage Dispenser C = 3 u
Beverage Dispenser E = 7 u 

Beverage Dispenser D + Beverage Dispenser C = 2799 --- (1)
Beverage Dispenser D + Beverage Dispenser E = 4083 --- (2)

(2) - (1)
(Beverage Dispenser D + Beverage Dispenser C) - (Beverage Dispenser D + Beverage Dispenser E) = 4083 - 2799
7 u - 3 u = 1284
4 u = 1284

1 u = 1284 ÷ 4 = 321
Beverage Dispenser C = 3 u = 321 x 3 = 963

Beverage Dispenser C + Beverage Dispenser D + Beverage Dispenser E = 963 + 4083 = 5046 mℓ

Average amount of water in the 3 beverage dispensers
= 5046 ÷ 3 
= 1682 mℓ

Answer(s): 1682 mℓ