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# The graph above shows the cumulative frequency curve of the distribution of mark...

### Question

The graph above shows the cumulative frequency curve of the distribution of marks in a class test. What percentage of the students scored more than 20 marks?

A) 68%

B) 28%

C) 17%

D) 8%

### Explanation:

$$\begin{array}{c|c} \text{class-marks(x)} & \text{(freq. (f)} & \text{cum. freq.}\\\hline 9 & &3.....3\\14 & & 6....3 + 6 = 9\\ 19 & & 9.....9 + 9 = 18\\ 24 & & 3.....18 + 3 = 21\\ 29 & & 2.....21 + 2 = 23\\ 34 & & 2.....23 + 2 = 25\\ & & 25\end{array}$$
% of students scoring more than 20 marks

= $$\frac{7}{25}$$ x 100% = 28%

## Dicussion (1)

• $$\begin{array}{c|c} \text{class-marks(x)} & \text{(freq. (f)} & \text{cum. freq.}\\\hline 9 & &3.....3\\14 & & 6....3 + 6 = 9\\ 19 & & 9.....9 + 9 = 18\\ 24 & & 3.....18 + 3 = 21\\ 29 & & 2.....21 + 2 = 23\\ 34 & & 2.....23 + 2 = 25\\ & & 25\end{array}$$
% of students scoring more than 20 marks

= $$\frac{7}{25}$$ x 100% = 28%