What is the price at the supermarket?

Question

I had just returned home in my car from the supermarket 2.5 miles away only to realise that I'd forgotten to buy something I needed. The convenience store across the road from my house had the item I needed, but the supermarket had the same item 35% cheaper. If my car's fuel consumption is 25 miles per gallon for short trips and fuel costs £4.90 a gallon, I worked out it that it was just as cheap to walk to the convenience store and buy the item as it was to drive to buy it from the supermarket. How much was the item at the  supermarket?

 

Answer 1

I had just returned home in my car from the supermarket 2.5 miles away only to realise that I'd forgotten to buy something I needed. The convenience store across the road from my house had the item I needed, but the supermarket had the same item 35% cheaper. If my car's fuel consumption is 25 miles per gallon for short trips and fuel costs £4.90 a gallon, I worked out it that it was just as cheap to walk to the convenience store and buy the item as it was to drive to buy it from the supermarket. How much was the item at the supermarket?

Travel distance = 2.5 miles * 2 = 5 miles

mpg = 25

Petrol required to travel = 1/5 gallon

Cost of travel = £4.90 * (1/5) = 98 p.

Let CS mean Convenience Store and Sm mean Supermarket.

CS-price = P, say.                           Sm-price = 0.65P

CS-cost = CS-price.                        Sm-cost = Sm-price + Cost of travel

P = 0.65P + 98

0.35P = 98

P = 98/0.35 = 280

Therefore Sm-price = 0.65P = 0.65 * 280 = 182p = £1.82

Comments

Dead right, as usual!