Assume that when adults with smart phones are randomly selected 45% use them in meetings or classes if 30 adult smart phone users are randomly selected find the probability that exactly 20 of them use their smart phones in meetings or classes

Acollege is selling tickets for a winter fund-raiser. one day, krissa sold 14 adult tickets and 8 student tickets for a total of $376. the next day, she sold 7 adult tickets and 11 student tickets for a total of $272. krissa wanted to find the price of one adult ticket, a, and the price of one student ticket, s. she wrote and solved the following system of equations.