Let the numbers be a, b, c, d, e, f, g, h, i and j
Then,
(a+b+c+d+e+f+g+h+i+j)/10 =x.................................(1)
If a is increased by 1, b by 2 and so on, then
New mean = {(a+1) + (b+2) + (c+3) + (d+4) + (e+5) + (f+6) + (g+7) + (h+8) + (i+9) + (j+10)}/10
= **{(a+b+c+d+e+f+g+h+i+j) + (1+2+3+4+5+6+7+8+9+10)}/10**
= **(a+b+c+d+e+f+g+h+i+j)/10 + 55/10**...........substitute eqn(1) to this eqn we have,
= **x + 5.5**
So the new mean (n.m) is,
**
n.m = x + 5.5
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