The bar chart

The bar chart shows the results of the math test. How many% of pupils achieved approximately better results than the average of the class?

Diagram: 1-10 pupils, 2-4 pupils, 3-6 pupils, 4-2 pupils, 5-4 pupils.
(lowest result are better)

Correct result:

p =  53.8462 %

Solution:

$$\begin{gathered} n=10+4+6+2+4=26 \\ a={\displaystyle \frac{1\cdot 10+2\cdot 4+3\cdot 6+4\cdot 2+5\cdot 4}{n}}={\displaystyle \frac{1\cdot 10+2\cdot 4+3\cdot 6+4\cdot 2+5\cdot 4}{26}}={\displaystyle \frac{32}{13}}\doteq 2.4615 \\ p=100\cdot {\displaystyle \frac{10+4}{n}}=100\cdot {\displaystyle \frac{10+4}{26}}={\displaystyle \frac{700}{13}}=53.8462\mathrm{\%} \end{gathered}$$

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