Yani buys a certain brand of cereal that costs $10 per box. Yani changes to a super-saving brand of the same size. The equation shows
the price, y, as a function of the number of boxes, x, for the new brand.
y = 7x
Part A: How many more dollars is the price of a box of Yani’s original brand of cereal than the price of a box of the super-saving cereal?
Show your work.
Part B: How much money does Yani save each month with the change in cereal brand if he buys 5 cereal boxes each month? Show your
work.
Answer:
A) Original price : y =10.x
Cheaper brand : y = 7x
The original box is $3 more than the cheap one.
Proof: Suppose 1 box is bought of each (x=1),Original will cost $10 & the Cheaper Price is $7
B) Each time he buys a cheap brand he save $3 ($10-$7).
On 5 cheap boxes, He would save $3 x 5 boxes = $15.
Step-by-step explanation:
Part A: The price of the first cereal that Yani bought was $10 and he new cereal is $7.
$10 – $7 = $3. The original box of cereal was $3 more than the super- saving cereal.
Part B: Yani will save $15 each month.
With the $10 cereal he used to pay $50 per month. Now with the super-saving cereal, he will now pay $35 per month.
So we need to subtract $50 – $35 = $15
A. Yani’s original brand of cereal is $3 more expensive.
His old brand cost $10 a box. His new brand cost can be determined by the slope of y=7x, thus it is $7. The difference between 10 and 7 is 3, thus there is a $3 difference.
B. Yani would save $15 per month buying the super-saving cereal.
Original: y = 10x
y=10(5)
y = $50
Super-saving: y = 7x
y=7(5)
y = $35
If Yani were to buy 5 boxes of the original cereal, he would spend $50. If she were to buy 5 boxes of the super-saving cereal, he would spend $35. The difference between 50 and 35 is 15, thus he would save $15 per month.