Question 887644
Jill paid $36 for calendars marked down $5 apiece from the original price.
 If she had bought them at the original price, she could have gotten 5 fewer calendars.
 How many calendars did she buy?
:
let x = the number of calenders she bought
let p = the original price
:
"Jill paid $36 for calendars marked down $5 apiece from the original price."
x(p - 5) = 36
px - 5x = 36
:
" If she had bought them at the original price, she could have gotten 5 fewer calendars."
p(x - 5) = 36
px - 5p = 36
then we can:
px - 5x = 36
px - 5p = 36
--------------Subtraction eliminates px
5p - 5x = 0
divide equation by 5
p - x = 0
therefore p = x
:
replace p with x in the 1st simplified equation
x*x - 5x = 36
form a quadratic equation
x^2 - 5x - 36 = 0
Factors to
(x-9)(x+4) =
only the positive solution wanted her
x = 9 calenders were bought
:
:
Confirm this, original price = $9
9(9 - 5) = 36



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