Madison and her sister received the same amount of money to go out to eat. each girl spent $13. after lunch, the girls had a total of $4. rite and solve an equation to find the amount of money each girl received

Each girl started with 15 dollars.

4$ is the ending amount
x= the amount of money each girl received
4= 2x - 2(13)        

Since there were two girls who both received x amount of money, x is multiplied by two. Since both the girls spent 13 dolars on lunch, their original amount is subtracted by 13 times two, since there are two lunches being bought. The end amount of money is four.
to solve:
4= 2x - 2(13)
4= 2x - 26       Simplify by combining like terms
30= 2x             Isolate the variable by adding 26 to both sides
15=x                Continue to isolate the variable by dividing both sides by two
Each girl started with 15 dolars. Each girl spent thirteen dolars on lunch and had two dolars left over. Each girls' two dolars left over adds up to four dollars.