( I will give brainlist) Mrs. Perkey solved the problem below. Oh no! It looks like she made a mistake! -3/5 + -2/5 = -1/5 What did she do wrong? Please explain how to solve this problem the correct way for full points.

Julius went on a volunteer trip to centralamerica and took medical supplies with him.he packed a bag with 50 pounds of supplies.he brought pieces of equipment that weighed10 pounds each and bottles of medicine thatweighed pound each prepresents thenumber of pieces of equipment he broughtand b represents the number of bottles ofmedicine he brought then the total weight canbe represented by the equation 10p+b 50.the brought 3 pieces of equipment, how manybottles of medicine did he bring?