Question

The phone case you want to buy is marked down 30%, and you have a 25% off coupon. You pay $42.00, can this equation be used to find the original price of the phone case? If so, what is the original price of the item? Explain.

Equation: 3/4(0.7c) =42

Please, someone just explain how I would use the equation. I don't want one word answers, give me a full paragraph if you have to. I've been told the answers 68.25 but I don't really know if it's right.

Answer 1

Yes that equation can be used.

The equation solves to c = 80

The original price is $80

==========================================================

Step-by-step explanation:

If you save 30%, then you pay the remaining 70%. That's where the 0.7 comes from in 0.7c

Also, if you save 25%, then you pay the remaining 75% aka 3/4.

To chain together discounts, we multiply them together, which is how we end up with the 3/4 times 0.7

To solve for c, we first multiply both sides by 4 to clear out the denominator. We're left with

3(0.7c) = 42*4

2.1c = 168

Then divide both sides by 2.1 to fully isolate c

c = 168/(2.1)

c = 80

The original price is $80

-------------

If you save 30%, then you save 0.30*80 = 24 dollars and the price is 80-24 = 56 dollars.

If you save another 25%, then you save 0.25*56 = 14 and the final price is 56-14 = 42 dollars which confirms we have the correct value for c.

Answer 2

Alright, so we know that the phone case was bought for 42$, we used a 25% coupon which if we did not have we would have bought the phone case for $56, which was already marked down 30% which if it wasn't the original price would have been $80 the original price.

the original price is $80, so whoever answered 68.25 was incorrect