Среднее арифметическое пяти чисел равно 10,5, а среднее арифметическое пятнадцати других чисел равно 12,1. Найдите среднее арифметическое этих двадцати чисел.
Спасибо за ранее)))

правильно подставить глаголы ;
1.A what ____ ____ doing on Sunday?
im going to the cinema
2.A ___ you ____ a computer
yes,i do,i use it  every day
3.what ___ ___ do last night?
i stayed at home and played computer games 
4.what ___ the teacher doing?
she is helping Aizhan with this exercise
5.what __ __like doing in your free time?
i like playing football
6.what ___ your father do?
he is a doctor . He works in hospital
7.what ____ you ___ at 5 o clock yesterday?
i was watching tv
8.How long ___ you ___ studying English ?
i ve been studying English for five years
9.what ___ you ___ to do tonight?
i m going to do my homework
10.зарание спс

помогите пожалуйста:

Грамматические признаки Им сущ., Им прил., Им мест., глагола.