Answer
31,200,000
Explanation
Firstly, calculate the constant of proportionality.
Al ∝ N
Al = kN Where Al = number of aluminium cans, k = constant and N = number of people using the can.
Al = kN
k = Al/N
= 120000/500
= 240
Equation becomes;
Al = 240N
For 130000 cans;
Al = 240 × 130000
= 31,200,000