maths (只有一題)

設首個數是(2n+1)

[(2n+1)+(2n+2)+(2n+3)] /3=12

2n+1+2n+2+2n+3=36

6n+6=36

6(n+1)=36

n=5

(2n+1)個數的中位數=(2n+2)
=(2 x 5 +2)
=12

答案應該係５.５