Mark bought a tshirt for d dollars. he paid 8% tax. the expression 1.08d represents the total amount that mark paid. what does the coefficient 1.08 mean in the context of this problem

The coefficient in this problem would represent the cost of the shirt with the tax!

Think about it like this

If a shirt costs 25 dollars and the tax is .08 per dollar then you would multiply 25*.08 to get two dollars

So in addition to the 25 dollars for the shirt, you would also have to pay the two dollars extra in taxes.

Meaning in total you would pay 27 dollars

So by adding the .08 to the whole which is in this case represented by 1

You would be accounting for both the price of the shirt and the tax!