Maths. problem 3 (5 marks)

好簡單!!
某3個數平均係13..
姐係13X3!!!
另外5個數平均係19!
姐係19X5!!
13X3+19X5 除 8 就OK啦!
答案係16.75!!!

let the original numbers be A, B and C respectively,

and D, E, F, G and H be the other 5 numbers,

becoz:

the sum of A, B and C = 13 x 3 = 39
the sum of D-H = 19 x 5= 95

therefore,
the mean for the 8 numbers is:

(39 + 95) / 8
= 16.75

i am 100 % sure it is correct!

這八個數的平均值=(13*3+19*5)/8
=(39+95)/8
=134/8
=16 3/4