Ok, so I used the equation Y2 (4) - Y1 (-10) over X2 (2) -X1 (-5).
4 - -10 is 14 since if a minus sign is before a negative number, it becomes positive.
Same goes for 2 - -5. It is 7 since the minus sign is before the negative number. Final answer is 14/7 which can be simpflied to 2/1 since 14 divided by 7 =2. So the distance is 14\7, or 2\1.
First, you have to find what 80% of 15 is. In order to do that you have to change 80% percent to decimal, which would be .80. Then, multiply .80 and 15 to get 12. Subtract 12 from 15 and your answer is 3.
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.
Answer:
let's hope for the best ....XD