The cost of gasoline tripled in the past 12 years. If gasoline cost n dollars and r cents per gallon 12 years ago, how much does it cost now?

Step-by-step explanation:

step one:

In this problem, we are told that the price of gasoline has tripled in the past twelve years.

step two:

Given that the price 12 years ago was $n and r cent

to get the current price we need to multiply the price twelve years ago by 3

hence n*3 and r*3

this means that the current price is

3n dollar and 3r cent

The price now is 3n dollar and 3r cent