Beverage Dispenser S and Beverage Dispenser T have a total amount of 1139 mℓ of water. For Beverage Dispenser T and Beverage Dispenser U, the total amount of water is 2829 mℓ. The amount of water in Beverage Dispenser S is ³₈ the amount of water in Beverage Dispenser U. What is the average amount of water in the 3 beverage dispensers?
Beverage Dispenser S = 3 u
Beverage Dispenser U = 8 u 

Beverage Dispenser T + Beverage Dispenser S = 1139 --- (1)
Beverage Dispenser T + Beverage Dispenser U = 2829 --- (2)

(2) - (1)
(Beverage Dispenser T + Beverage Dispenser S) - (Beverage Dispenser T + Beverage Dispenser U) = 2829 - 1139
8 u - 3 u = 1690
5 u = 1690

1 u = 1690 ÷ 5 = 338
Beverage Dispenser S = 3 u = 338 x 3 = 1014

Beverage Dispenser S + Beverage Dispenser T + Beverage Dispenser U = 1014 + 2829 = 3843 mℓ

Average amount of water in the 3 beverage dispensers
= 3843 ÷ 3 
= 1281 mℓ

Answer(s): 1281 mℓ