the price of a notebook was $3.15 yesterday. today, the price rose to $3.40. find the percentage increase…

Explanation:

Step1: Calculate the increase amount

The increase amount is the difference between the new price and the original price. $3.40 - 3.15=0.25$

Step2: Calculate the percentage increase

The formula for percentage increase is $\frac{\text{increase amount}}{\text{original amount}}\times100%$. Substitute the values: $\frac{0.25}{3.15}\times 100%$ $=\frac{25}{3.15}%$ $\approx 7.9%$ (rounded to the nearest tenth of a percent)

Answer:

$7.9%$