Find original given discount
Teaching Point: to find the original price
when given the discounted price and rate
HW: See Website
DO NOW:
For each example, find what percent of the original price is being paid
and what percent of the original price is being saved.
1. An item is discounted 30%.
2. An item is discounted 0%
3. An item is discounted 100%
4. An item is discounted 2%
Percent Proportion
November 14, 2014
In today's lesson we will be given the
adjusted price (sale price) and we will
need to find the original price.
When given the sale price and the
percent, to find the original we must first
find the percent paid.
A proportion or an equation can be
used to find the original price.
MODEL:
A shirt is on sale for 40% off. The sale price is $12.
What was the original price?
adjusted price
(a.k.a.sale price)
Original
What was the amount of the discount?
= adjusted percent
100
this means that you are paying
60% of the original cost.
so: you want to find 60% of what is $12?
sale price is
given not the
original price
Find original given discount
TRY IT:
Stephanie paid $120 for a necklace when she used a 25%
discount coupon. Find the original price.
Practice:
A: 1. Given: Sale price = $45; percent discount 25%;
2.
B:
find the original price
Given: Sale price = $72; percent discount 40%;
find the original price
Critique Genna’s work. Is she correct? Explain. If not, solve the problem
correctly.
Genna left the store happy because after a 30% discount, she paid
$150.50 for her items. She was ecstatic because she saved $60.50!
C: Given: sale price is $45.50 after two discounts are
applied. 20% off the original price, then 30% off
the sale price. Find the original price.
Enrichment: Mcdougal pg. 361 Brain Game
November 14, 2014
1 Pre Activity Assessment: The sale price of an item is $22
after a 25% discount was applied. What was the original
price?(round your answer to the nearest hundredth)
Summary: What did you learn today?
How is finding the original price different from
finding the sale price?
Find original given discount
Summary:
Look at this problem. Explain what is wrong
with the equation set-up:
November 14, 2014
1.
2.
Given: Sale price = $45; percent discount 25%;
find the original price
Given: Sale price = $72; percent discount 40%;
find the original price
Stephanie paid $120 for a necklace when she used a 40%
discount coupon. Find the original price.
40%(120) = original price
Critique Genna’s work. Is she correct? Explain. If not, solve the problem
correctly.
Genna left the store happy because after a 30% discount, she paid
$150.50 for her items. She was ecstatic because she saved $60.50!
Given: sale price is $45.50 after two discounts are
Given:
sale
is $45.50
after
two30%
discounts
are
applied.
20%
off price
the original
price,
then
off
applied.
original
price, then 30% off
the sale
price. 20%
Find off
thethe
original
price.
the sale price. Find the original price.
Find original given discount
November 14, 2014