Problem Solving

Kim purchased n items from a catalog for $8 each. Postage and handling charges consisted of $3 for the first item and $1 for each additional item. Which of the following gives the total dollar amount for Kim's purchase, including postage and handling, in terms of n ?

(A) 8n + 2
(B) 8n + 4
(C) 9n + 2
(D) 9n + 3
(E) 9n + 4

The OA is C.

I am confused. I thought the correct answer should be A. Why is C?

VJesus12 wrote:Kim purchased n items from a catalog for $8 each. Postage and handling charges consisted of $3 for the first item and $1 for each additional item. Which of the following gives the total dollar amount for Kim's purchase, including postage and handling, in terms of n ?

(A) 8n + 2
(B) 8n + 4
(C) 9n + 2
(D) 9n + 3
(E) 9n + 4

The OA is C.

I am confused. I thought the correct answer should be A. Why is C?

Cost of Items: If Kim purchases n items for $8 each, then she spends a total of 8n on those items.

Postage and Handling: We know that the first item carries a charge of $3. If there are a total of n items purchased, after the first item, there will be an additional n -1 items. If the charge is $1 each for those n -1 items, then she'll spend 1(n-1) dollars on those, for a total of 3 + 1(n - 1) = 3 + n - 1 = n + 2 dollars.

So she spent 8n on the items and n + 2 on postage, for a total of 8n + n + 2 = 9n + 2 dollars. The answer is C

VJesus12 wrote:Kim purchased n items from a catalog for $8 each. Postage and handling charges consisted of $3 for the first item and $1 for each additional item. Which of the following gives the total dollar amount for Kim's purchase, including postage and handling, in terms of n ?

(A) 8n + 2
(B) 8n + 4
(C) 9n + 2
(D) 9n + 3
(E) 9n + 4

The OA is C.

I am confused. I thought the correct answer should be A. Why is C?

You could also pick an easy number. Say n = 5. If she bought 5 items for $8 each, she'll spend 5*8 = $40.
The first item carries a postage charge of $3. The other 4 carry a charge of $1 each for a total postage charge of 3 + 4 = $7
Total spent: 40 + 7 = 47. This is our target.

Now just plug '5' in place of 'n' in the answer choices until we find that value of 47. Only C will work. (9*5 + 2 = 45 + 2 = 47.)