Explanation:
30
The mean of 10, 15, 19, 30, 43, 69 and x is x.
\(\therefore\text{Mean}=\frac{\text{Sum of observations}}{\text{Number of observations}}\)
\(\Rightarrow\text{x}=\frac{10+15+19+30+43+69+\text{x}}{7}\)
\(\Rightarrow\text{x}+186=7\text{x}\)
\(\Rightarrow\text{x}=\frac{186}{6}=31\)
Thus, the observations are 10, 15, 19, 30, 43, 69 and 31
Arranging the numbers 10, 15, 19, 30, 43, 69 and 31 in increasing order, we get
10, 15, 19, 30, 31, 43, 69
Thus, the median is 30
Hence, the correct option is (c).