N.B. I believe your question is saying that the price of a cup of coffee was $2.40 yesterday, and it rose to $2.65 today. Therefore, I will solve with these prices.
The percent increase is 10.41666666% (The 6 is repeating.).
First, you find the difference, or increase, between the two prices.
New price - Old price = Increase
$2.65 - $2.40 = $0.25
The difference between the two prices is $0.25. To find the percent increase, you want to divide the original price ($2.40) from the increase ($0.25) and multiply by 100.
Increase ÷ Original Price × 100 = % increase
0.25 ÷ 2.40 × 100 = 10.41666666%
The percent increase is 10.41666666% (The 6 is repeating.).
