Hannah placed an online order for shirts that cost $24.50 per shirt. A tax of 7% is added to the cost of the shirts, before a flat, untaxed shipping rate of $6 is charged. Which of the following represents Hannah's total cost for s shirts, in dollars?
A. 0.07(24.50s + 6)
B. 1.07(24.50 + 6)s
C. 1.07(24.50s) + 6
D. 1.07(24.50 + s) + 6
Answer:C
Hannah placed an online order for shirts that cost $24.50 per shirt. A tax of 7% is added to the cost of the shirts, before a flat, untaxed shipping rate of $6 is charged. Which of the following represents Hannah's total cost for s shirts, in dollars?
A. 0.07(24.50s + 6) B. 1.07(24.50 + 6)s C. 1.07(24.50s) + 6 D. 1.07(24.50 + s) + 6
Explanation: C Whenever the question includes variables, plug in. If s = 2, the shirts cost 2($24.50) = $49. The tax on the shirts is 0.07($49) = $3.43. So, the shirts with tax and the $6 shipping fee cost $49 + $3.43 + $6 = $58.43. Plug in 2 for s in the answers to see which answer equals the target number of $58.43. In (A), 0.07[24.50(2) + 6] = 3.85. This is not the target number, so eliminate (A). In (B), 1.07(24.50 + 6)(2) = 65.25. Again, this is not the target number, so eliminate (B). In (C), 1.07[24.50(2)] + 6 = 58.43. This is the target number, so keep it, but be sure to check the remaining answer choice. In (D), 1.07(24.50 + 2) + 6 = 34.355, which is not the target number. Therefore, the correct answer is (C).