The percent of the increase is
I is the increasing value
N is the new value
O is the original value
The price of the cooler is $28.50, then
O = 28.50
The selling price of the cooler is $40.76, then
N = 40.76
We will substitute them in the rule above to find I
Let us calculate it
I = 43.0175 %
Round it to the nearest percent
I = 43%
The answer is D