Answer:
The cost of 15 liters is $31.50
Step-by-step explanation:
1. Find the price for 1 liter of petrol.
Divide the cost by the number of liters:
$14.70 / 7 = $2.10 per liter.
2. Multiply the price for 1 liter by the new number of liters, 15.
$2.10 per liter x 15 liters = $31.50
