Задача Статистика № 7

Task 1.
There is information on the number of students in the universities of the city and the proportion () of students studying on a commercial basis:
Universities of the city The total number of students (thousand people) Of them, the proportion (), studying on a commercial basis.
USTU—UPI 15 15
USUE 3 10
UrGUA 7 20
Define:
1) the average proportion of university students studying on a commercial basis;
2) the number of these students.

ask 1.
There is information on the number of students in the universities of the city and the proportion () of students studying on a commercial basis: