After a 20% discount, followed by a 20% tip, the price of a meal for two is $24. What was the original price for both meals?

Question

I know the answer to this question but one step still confuses me. I know a 20% tip is really 1.2, so my teacher did 1.2y=24. She made “y” the amount of the original meal with the discount. I don’t understand why you would multiply the tip to the amount of the original meal.

Answer 1

This is a matter of personal choice. Most polite people shall calculate the tip on the original amount of the meal.

x represents the original amount

0.8x represents the after discount amount

0.2x represents the tip on original amount

0.8x + 0.2x = 24

x = 24.

Now let's suppose that the customer is a cheap skate and tips on the discounted amount.

x represents the original amount

0.8x represents the after discount amount

0.16 represents the tip on the discounted amount

0.8x + 0.16x = 24

0.96x = 24

x = 25

The problem is an example of an "authentic assessment" that does not consider reality.

Answer 2

So, when you go out to eat with a coupon, you tip on the price before the coupon. Yeah, you're getting a discount on the food, but you didn't get 80% service (at least I hope not).

You really don't even need to do any math. If I take 20% off and add 20% back on, I'm at what I started with, so the original cost of the meal was $24.

Note, this would not be the case if I only tipped on the discounted price. In that case, I'm paying 120% of 80% of the original cost, so...

1.2(0.8)y = 24

0.96y = 24

y = $25

Answer 3

Let assume original price of meal = Y

1) After 20% discount price of meal = $24

Here discount amount = Price of meal * Discount rate = Y * 20% = 0.20 * Y

Net price of meal = Original price of meal - Discount amount

$24 = Y - 0.20 * Y

$24 = 0.80 * Y

Y = $24 / 0.80 = $30

Ans : Original price of meal , Y = $30

2) Followed by 20% tip, price of meal = $24

That means here we are paying extra 20% of price as a tip to the server. So our total cost is original price

of meal and tip amount.

Tip amount = Original price of meal * tip rate = Y * 20% = 0.20 * Y

Net price of meal = Original price + Tip amount

$24 = Y + 0.20 * Y

$24 = 1.20 * Y

Y = $24 / 1.20 = $20

Ans : Original price of meal, Y = $20