Question

He average of 5 numbers is 7. When 3 new members are added, the average of the eight numbers is 8.5. The average of three new numbers is

Answer 1

Answer:

The average of three numbers is 11.

Step-by-step explanation:

Given that the average of 5 numbers is 7.

let the numbers be x, x+1, x+2, x+3 and x+4

So, (x+x+1+x+2+x+3+x+4)/5 = 7

5x +10 = 35

5x = 25

x= 5

So, the respective five numbers are 5, 6, 7, 8 and 9

Now given that when three more numbers are added the average becomes 8.5

let the three numbers be a, a+1 and a+2

So, (5 + 6 + 7+ 8+ 9 +a + a+1 + a+2)/8 = 8.5

3a + 38 = 68

3a = 30

a = 10

So the three numbers are 10, 11 and 12

Now, the average of three numbers = (10 + 11 + 12)/3

                                                            = 33/3

                                                            = 11