Cylinder A and Cylinder B have a total amount of 2874 mℓ of water. For Cylinder B and Cylinder C, the total amount of water is 3153 mℓ. The amount of water in Cylinder A is ²₅ the amount of water in Cylinder C. What is the average amount of water in the 3 cylinders?
Cylinder A = 2 u
Cylinder C = 5 u 

Cylinder B + Cylinder A = 2874 --- (1)
Cylinder B + Cylinder C = 3153 --- (2)

(2) - (1)
(Cylinder B + Cylinder A) - (Cylinder B + Cylinder C) = 3153 - 2874
5 u - 2 u = 279
3 u = 279

1 u = 279 ÷ 3 = 93
Cylinder A = 2 u = 93 x 2 = 186

Cylinder A + Cylinder B + Cylinder C = 186 + 3153 = 3339 mℓ

Average amount of water in the 3 cylinders
= 3339 ÷ 3 
= 1113 mℓ

Answer(s): 1113 mℓ