d + 0.18d

F. The cost plus eighteen percent of the cost

G. the cost minus eighteen percent of the cost

H. the cost plus eight percent of the cost

J. The cost plus one hundred eighteen percent of the cost

I think the answer is F.

I really dont get this question

A merchant spend $92 to buy a calculator

then the merchant sold it with a 21% markup. Katherine used her calculator and found the amount of the markup to be $9.

Explain how you can use estimation to check the reasonableness of Katherine's

calculation

part B

Without doing calculation, tell whether or not Katherine's calculation is reasonable explain your answer

I really dont get this question can u help me