The following table shows the distribution of the marks obtained by 50 students in an aptitude test.

Marks obtained	No. of students
15	6
18	18
21	12
24	8
27	4
30	2

Find the mean, the median and the mode of the distribution.

By formula,

Mean = $\dfrac{Σfx}{Σf} = \dfrac{1026}{50}$ = 20.52

From table,

n (no. of terms) = 50, which is even.

By formula,

Median = $\dfrac{n}{2}$ th term

= $\dfrac{50}{2}$ = 25th term.

From table,

Marks obtained from 25th to 36th student = 21.

∴ Median = 21.

Maximum students have scored 18 marks.

∴ Mode = 18.

Hence, mean = 20.52, median = 21 and mode = 18.