Question

the average age of 12 boys is 8 years . another boy 21 years. join the group . find the average of the new group.​

Answer 1

Answer:

lowest form

Step-by-step explanation:

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Answer 2

Answer:

Average of new group will be 9.

Step-by-step explanation:

Because,

Let, the 12 boys be a, b, c, d, e, f, g, h, I, j, k, L.

Therefore, Average =

(a+b+c+d+ e+f+g+h+I+j+k+L)/12 = 8

or, a+b+c+d+ e+f+g+h+I+j+k+L = 8*12

or, a+b+c+d+ e+f+g+h+I+j+k+L = 96

Therefore, Sum of age of 12 boys = 96 years.

Since, One another boys joined them whose age is 21 years.

Let another boys be M

therefore,

a+b+c+d+ e+f+g+h+I+j+k+L+M = 96 +M

or, a+b+c+d+ e+f+g+h+I+j+k+L+21 = 96 +21

or, or a+b+c+d+ e+f+g+h+I+j+k+L+21 = 117

Therefore, Sum of all 13 boy's years = 117

Hence average= 117/13

= 9