Cylinder K and Cylinder L have a total amount of 2763 mℓ of water. For Cylinder L and Cylinder M, the total amount of water is 4860 mℓ. The amount of water in Cylinder K is ⁴₇ the amount of water in Cylinder M. What is the average amount of water in the 3 cylinders?
Cylinder K = 4 u
Cylinder M = 7 u 

Cylinder L + Cylinder K = 2763 --- (1)
Cylinder L + Cylinder M = 4860 --- (2)

(2) - (1)
(Cylinder L + Cylinder K) - (Cylinder L + Cylinder M) = 4860 - 2763
7 u - 4 u = 2097
3 u = 2097

1 u = 2097 ÷ 3 = 699
Cylinder K = 4 u = 699 x 4 = 2796

Cylinder K + Cylinder L + Cylinder M = 2796 + 4860 = 7656 mℓ

Average amount of water in the 3 cylinders
= 7656 ÷ 3 
= 2552 mℓ

Answer(s): 2552 mℓ