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.
I think they would go to the rational numbers
~Hello There!~
Finding the perimeter simply means adding all the sides together.
31 + 81 + 31 + 81 = 224 cm
Yes, you are correct.
Hope This Helps You!
Good Luck :)
Have A Great Day ^_^
- Hannah ❤
Answer:
134.
Step-by-step explanation:
87 - (-34) +13 (Note -(-34) = + 34):
= 87 + 34 + 13
= 121 + 13
= 134.
Answer: 1/2
Explanation:
1/2 is 50
1/4 is 25
25<50