The answer to this question is 1:5
Answer: The average was 9 years old find the average age of both groups is 10 years old.
Step-by-step explanation:
Formula foe average : 
Given : The first group of students consists of 10 and their average age was 13 years old.
i.e.
(1)
The next group consisted of 30 students and their average was 9 years old.
i.e.
(2)
Then from (1) and (2) , the sum of both groups (first group and next group )students = 130+270 =400
Combined students of both groups (first and next group )= 10+30=40
Now , the average of both groups =

Hence, the average was 9 years old find the average age of both groups is 10 years old.
For one semester a School A-
750 + 200 = 950
For one semester at School B-
10 percent off of 1,000 is 900
School A- $950
School B- $900
Answer:
1/5 is equal to 20% so you multiply 48 by .20 and you get 9.6 and your take 9.6 and add it to 48. your answer will be 57.6
3.75.....rounded to the nearest dollar would be 4.00