Word problem

[lfalgoust02]

I am very bad at word problems!! Can someone help me out, please?


A bakery sells three kinds of cookies; chocolate chip at .15 cents each, oatmeal at .20 cents and peanut butter at .25 cents.

You buy some of each kind, but choose 3 times as many peanut butter as chocolate chip.

If you spend $4.10 on 19 cookies, how many of each kind did you buy?

 

[Xeris]

Answer

First you have to set up and equation. Two of them to be exact.
one of them is:

3X + X + Y = 19 this is how many cookies there are.

X stands for the amount of chocolate chip cookies and 3X is the amount of peanut butter since there is 3 times as many peanut butter then chocolate chip cookies. And Y is obviously oatmeal cookies.

The other equation is:
3X(.25) + X(.15) + Y(.2) = $4.10 this is the cost of each cookie.

The first term is to calculate the cost of the peanut butter cookies and the second term is to calculate the cost of chocolate cookies and the third term is to calculate the cost of oatmeal cookies.

Then you have to substitute for Y which will then let you calculate for X. With X solved all you have to do is plug everything in. You will end up getting this answer:

3 Chocolate Chip cookies
9 Peanut Butter cookies
7 Oatmeal cookies

That gives you 19 cookies.

 

[arthur ohlsten]

let C be number of Chocolate chip
O the number of oatmeal
P the number of peanut butter

C+P+O=19
P=3C
.15C+.20 O + .25P=4.10

but C+3C+O=19 from eq1 and eq2
O= 19-4C substitute into 3rd equation
.15C+.25[3C] +.2[19-4C] =4.10
.15C+.75C+3.8 -.8C=4.1
.1C= .3
C=3 answer
P=9 answer
O=7 answer
Arthur

 

[Xeris]

Yea I did that at first but I was getting confussed with my O's being 0's lol.