Well first you have to see that there is 4 people going ari and his 3 brothers. Then I multiplied 4 people times 18 dollars a week. I got 72. After that I multiplied 72 dollars by 4 because of the 4 weeks they will be collecting money and I got 288. Lastly I added the 288$ to the 320 dollars they already saved and in total I got $608.
