The cost of a protein bar increased from $2.50 to $2.80. What is the percent increase?

• A. 16%
• B. 10%
• C. 15%
• D. 12%

Answer: (D)

To determine the percent increase in the cost of the protein bar, you start by calculating the difference between the new price and the old price. The new price is $2.80, and the old price is $2.50.

First, you find the difference:

$2.80 - $2.50 = $0.30.

Next, to find the percent increase, you divide the difference by the original price:

$0.30 ÷ $2.50 = 0.12.

Lastly, to convert this decimal to a percentage, you multiply by 100:

0.12 × 100 = 12%.

Thus, the percent increase in the cost of the protein bar is 12%. This method effectively measures how much the price has risen relative to its original cost, providing a clear view of the increase’s significance.