SME
Grade 7 Math · Problem type
Discount and sale price
Use this for “A $64 coat is 30% off. What is the sale price?”
Diagram
25% of $60 = $15
$60 − $15 = $45
This is an example. Type your own values to start a new problem.
p
%
of
$
w
=
$
c
$
w
−
$
c
=
$
T
Formulas
c
=
w
×
p
÷
100
(discount
=
price
×
percent
off
÷
100)
15 = 60 × 25 ÷ 100
T
=
w
−
c
(sale
price
=
price
−
discount)
45 = 60 − 15
T
=
w
×
(100
−
p
)
÷
100
(sale
price
=
price
×
(100
−
percent
off)
÷
100)
45 = 60 × (100 − 25) ÷ 100
Assumptions
•
The price is 100%. The discount is p% of it.
•
The sale price is 100% − p% of the price.
•
To find the original price, the sale price is (100 − p)% of it.
•
Round money to the nearest cent.
Step-by-step
WE KNOW
w = $60 (price), p = 25% (percent off)
FIND
discount (c), sale price (T)
Step 1 · Find discount (c)
Use c = w × p ÷ 100 (discount = price × percent off ÷ 100)
The
discount
is
p
%
of
the
price.
c
=
60
×
25
100
c
=
1,500
100
c
=
$15
Step 2 · Find sale price (T)
Use T = w − c (sale price = price − discount)
Take the discount off the price.
T
=
60
−
15
T
=
$45
Check
Put the numbers back in. Both sides should match.
15 = 60 × 25 ÷ 100 ✓
45 = 60 − 15 ✓
45 = 60 × (100 − 25) ÷ 100 ✓
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Tax, tip, markup, discount and percent change
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Percent increase and decrease
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