Dear student
Tanker has capacity of 15KL 500 I = (15000 + 500) Litres = 15,500 litres
So each petrol pump has capacity of 720 litres
let there are x petrol pumps so as
1 hold 720 litres
x holds 15,500 litres.
= 21.52
so 21 petrol stations can be supplied with the petrol of the tank with some petrol left in tanker.
Regards.