c = 1.05p
Step-by-step explanation:
Price of the hat = p
Percentage increase in the price of the hat = 5%
The equation to calculate the increase of the total cost, c, of the hat will be:
c = p + (5% × p)
= p + (5/100 × p)
= p + (0.05 × p)
= p + 0.05p
c = 1.05p