There are several cookies in the jar. Taking 1 cookie away would leave half as many in the jar as if 5 were added. How many cookies are in the jar?
Let C be the number of cookies
There would be C-1 cookies.
There would be (C+5)/2 cookies.
C-1=(C+5)/2.
2(C-1)=C+5
2C-2=C+5
C=<<7=7>>7
#### 7