The bar graph shows the data of the students who appeared and passed in an examination for four schools $P, Q, R$, and $S$. The average of success rates $\text{(in percentage)}$ of  these four schools is _______.

1. $58.5\%$
2. $58.8\%$
3. $59.0\%$
4. $59.3\%$

We can calculate the success rate of every school, then find their average.

Success rate $= \dfrac{\text{Number of students who passed the exams}}{\text{Number of appeared students}}$

• Success rate of school $P = \dfrac{280}{500} \times 100\% = 56\%.$
• Success rate of school $Q = \dfrac{330}{600} \times 100\% = 55\%.$
• Success rate of school $R = \dfrac{455}{700} \times 100\% = 65 \%.$
• Success rate of school $S = \dfrac{240}{400} \times 100\% = 60\%.$

Now, the average success rates of all the schools $= \dfrac{56\% + 55\% + 65\% + 60\%}{4} = \dfrac{236\%}{4} = 59.0\%.$

So, the correct answer is $(C).$

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