A survey found that one out of five Americans says he or she has visited a doctor in any given month. If 10 people are selected at random, find the probability that at least 3 will have visited a doctor last month.

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