Iwon tickets to a trip for four to the super bowl. i have eight friends but i can only bring three of them. in how many ways can i form my super bowl party?

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of