Donavon and three friends go to a fair. they each spend one half of their money on rides. then, they each spend $3 on food. at the end of the day, donavon and his friends have a total of $8 remaining. how much money did each person bring to the fair?

You have to work backwards on this type of problem. Since there is $8 to split amongst the 4 kids, they each have $2 left. $2 + $3 for food = $5. Double that since they spent HALF of their original amount on rides and that gives you $10 that they started with.