Question

Luke buys a certain brand of cereal that costs $11 per box. Luke 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 = 9x

Part A: How many more dollars is the price of a box of Luke's original brand of cereal than the price of a box of the super-saving brand? Show your work.

Part B: How much money does Luke save each month with the change in cereal brand if he buys 6 cereal boxes each month? Show your work.

Answer 1

y = 11x is the function for the original boxes that he bought...it was $11 per box.

y = 9x is the function for the super saving brand...it is $9 per box

so there is a $2 difference between the original and the super saver.

original box.....6 cereals
y = 11(6)
y = 66

super saver....6 cereals
y = 9(6)
y = 54

66 - 54 = 12.....so Luke saves $12 per month by buying the super saver brand

Answer 2

Basically, the function for the first cereal is

`y=11x`

Because, the problem states that it costs $11 per box.

Now, the another cereal that Luke decides to by is $9 per box, which is expressed

`y=9x`

Now, the difference between the costs is $2, because 11-9=2. So, the original brand costs $2 more than the super-saving brand.

Now, if Luke buys 6 cereal boxes per month, the cost in each case would be

`y=11(6)=66\\y=9(6)=54`

This means that Luke is saving per month 66-54=12. So, by buying 6 cereal boxes of the second choice, he will save $12 per month.