We have 2 pieces of information that will give a pair of simultaneous equations to solve. First, take c to be the number of chocolate cookies and take r to be the number of raisin cookies.
We are told that the total number of cookies made is 168, so it will follow that:
We are also told that there are 22 more chocolate cookies so their difference is 22:
To use substitution, rearrange the 2nd equation to get c on one side:
Now we can replace
Rearrange this to obtain
So there are 73 raisin cookies. Now going back to the simultaneous equations, we now have a value for
Hence there 95 chocolate cookies and 73 raisin cookies.
Define your variables:
Then we know two things:
We may now replace (substitute) the number
So he made
Check your result: