HELP ME PLZZ I NEED HELP WITH THIS!!

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?

The relative growth rate for a certain type of fungi is 60% per hour. a small culture has formed and in just 6 hours the count shows to be 20,273 fungi in the culture. what is the initial number of fungi in the culture?

Acompany that makes? hair-care products had 5000 people try a new shampoo. of the 5000 ? people, 35 had a mild allergic reaction. what percent of the people had a mild allergic? reaction?