Cylinder F and Cylinder G have a total amount of 1756 mℓ of water. For Cylinder G and Cylinder H, the total amount of water is 2704 mℓ. The amount of water in Cylinder F is ⁵₈ the amount of water in Cylinder H. What is the average amount of water in the 3 cylinders?
Cylinder F = 5 u
Cylinder H = 8 u 

Cylinder G + Cylinder F = 1756 --- (1)
Cylinder G + Cylinder H = 2704 --- (2)

(2) - (1)
(Cylinder G + Cylinder F) - (Cylinder G + Cylinder H) = 2704 - 1756
8 u - 5 u = 948
3 u = 948

1 u = 948 ÷ 3 = 316
Cylinder F = 5 u = 316 x 5 = 1580

Cylinder F + Cylinder G + Cylinder H = 1580 + 2704 = 4284 mℓ

Average amount of water in the 3 cylinders
= 4284 ÷ 3 
= 1428 mℓ

Answer(s): 1428 mℓ