At a supermarket, a certain item has increased from 75 cents per pound to 81 cents per pound. What is the percent increase in the cost of the item?

There was an 8% increase in the cost of the item.

If the price of gas increases from $1.00 per gallon to $1.21 per gallon, what is the percent of increase?

The percent of increase is 21%.

As soon as a new car is purchased and driven away from the dealership, it begins to lose its value, or depreciate. Alonso bought a 1994 Plymouth Neon for 500. One year later, the value of the car was 438. What was the percent of decrease of the value of the car?

The percent of decrease was %