Question

Tasty bakery sells three kinds of cookies Chocolate chip at $.30 each oatmeal raisin at $.35 each and peanut butter at $.40 each can despise some of each kind and choose is twice as many peanut butters is chocolate chip if she spends $5.75 on 16 cookies how many oatmeal raisin cookies did she buy

Answer 1

She buy 7 oatmeal raisin cookies.

Explanation:

Given:

Tasty bakery sells three kinds of cookies Chocolate chip at $.30 each oatmeal raisin at $.35 each and peanut butter at $.40 each.

She buys some of each kind and chooses twice as many peanut butters as chocolate chip.

If she spends $5.75 on 16 cookies.

Now, to find the quantity of oatmeal raisin cookies she buy.

Let the quantity of oatmeal raisin cookies be
`x.`

And let the quantity of Chocolate chip cookies be
`y`.

So, the quantity of peanut butter cookies is
`2y.`

Now, the total quantity of cookies:

`x+y+2y=16\\\\x+3y=16\\\\x=16-3y\ \ \ \ .....(1)`

Now, the total money she spends on buying cookies:

`0.30(y)+0.35(x)+0.40(2y)=5.75`

Substituting the value of
`x` from equation (1):

`0.30(y)+0.35(16-3y)+0.40(2y)=5.75\\\\0.30y+5.6-1.05y+0.80y=5.75\\\\5.6+0.05y=5.75`

Subtracting both sides by 5.6 we get:

`0.05y=0.15`

Dividing both sides by 0.15 we get:

`y=3.`

The quantity of Chocolate chip cookies = 3.

Now, to substitute the value of
`y` in equation (1) to get the quantity of oatmeal raisin cookies:

`x=16-3y\\\\x=16-3(3)\\\\x=16-9\\\\x=7.`

The quantity of oatmeal raisin cookies = 7.

Therefore, she buy 7 oatmeal raisin cookies.