Beverage Dispenser M and Beverage Dispenser N have a total amount of 978 mℓ of water. For Beverage Dispenser N and Beverage Dispenser P, the total amount of water is 3438 mℓ. The amount of water in Beverage Dispenser M is ³₇ the amount of water in Beverage Dispenser P. What is the average amount of water in the 3 beverage dispensers?
Beverage Dispenser M = 3 u
Beverage Dispenser P = 7 u 

Beverage Dispenser N + Beverage Dispenser M = 978 --- (1)
Beverage Dispenser N + Beverage Dispenser P = 3438 --- (2)

(2) - (1)
(Beverage Dispenser N + Beverage Dispenser M) - (Beverage Dispenser N + Beverage Dispenser P) = 3438 - 978
7 u - 3 u = 2460
4 u = 2460

1 u = 2460 ÷ 4 = 615
Beverage Dispenser M = 3 u = 615 x 3 = 1845

Beverage Dispenser M + Beverage Dispenser N + Beverage Dispenser P = 1845 + 3438 = 5283 mℓ

Average amount of water in the 3 beverage dispensers
= 5283 ÷ 3 
= 1761 mℓ

Answer(s): 1761 mℓ