Correct Answer  Option 2 : 33.3
Concept:
 \({\rm{Mean}} = \frac{{\sum {\rm{xf}}}}{{\sum {\rm{f}}}}\)
Calculation:
Age

Frequency (f)

x

xf

10 – 20

4

15

60

20 – 30

6

25

150

30 – 40

8

35

280

40 – 50

2

45

90

50  60

4

55

220


\(\sum {\rm{f}} = 24\)


\(\sum {\rm{xf}} = 800\)

We know that, \({\rm{Mean}} = \frac{{\sum {\rm{xf}}}}{{\sum {\rm{f}}}}\)
\(\therefore {\rm{Mean}} = \frac{{800}}{{24}} = 33.3\)