Percents

[BTGmoderatorRO]

An item is being sold for $10 each. However, if a customer will "buy at least 3" they have a promo discount of 12%. Also, if a customer will "buy at least 10" items they will deduct an additional 8% to their "buy at least 3" promo price. If Sam buys 10 pcs of that item how much should he pay?

(A) $92.00
(B) $88.00
(C) $87.04
(D) $80.96
(E) $80.00

OA is D

What percentage formula could be used here? An Expert contribution will be highly welcomed.

[EconomistGMATTutor]

Hello Roland2rule.

Let's take a look at your question.

If Sam buys 10 pcs, without the promo discount he should pay 100$.

Since he brought "at least 3" he won the first promo discount, hence he had to pay 88% of the total price. So, he should pay 88%*100$ = 88$.

Now, since he brought 10 items, he won the second promo discount ("buy at least 10"). So, he had to pay the 92% of the secondary cost. Therefore, he should pay 92%*88$ = 80.96$.

This is why the correct answer is the option D.

I hope this explanation may help you.

I'm available if you'd like a follow-up.

Regards.