Beverage Dispenser R and Beverage Dispenser S have a total amount of 3953 mℓ of water. For Beverage Dispenser S and Beverage Dispenser T, the total amount of water is 4377 mℓ. The amount of water in Beverage Dispenser R is ³₇ the amount of water in Beverage Dispenser T. What is the average amount of water in the 3 beverage dispensers?
Beverage Dispenser R = 3 u
Beverage Dispenser T = 7 u 

Beverage Dispenser S + Beverage Dispenser R = 3953 --- (1)
Beverage Dispenser S + Beverage Dispenser T = 4377 --- (2)

(2) - (1)
(Beverage Dispenser S + Beverage Dispenser R) - (Beverage Dispenser S + Beverage Dispenser T) = 4377 - 3953
7 u - 3 u = 424
4 u = 424

1 u = 424 ÷ 4 = 106
Beverage Dispenser R = 3 u = 106 x 3 = 318

Beverage Dispenser R + Beverage Dispenser S + Beverage Dispenser T = 318 + 4377 = 4695 mℓ

Average amount of water in the 3 beverage dispensers
= 4695 ÷ 3 
= 1565 mℓ

Answer(s): 1565 mℓ