Answer: 30.85%.
Explanation:
Let X denotes the score of random student.
Given:
and

We assume that scores are normally distributed.
Then , the probability that a a student score higher than 55:
![P(X>55)=P((X-\mu)/(\sigma)>(55-50)/(10))\\\\=P(Z>0.5) \ \ [Z=(X-\mu)/(\sigma)]\\\\=1-P(Z<0.5)\\\\=1-0.6915\ [\text{By p-value table for z}]\\\\= 0.3085](https://img.qammunity.org/2021/formulas/mathematics/high-school/szu9m6jqu5e6k12dte77fryvjmdswoolv6.png)
Hence, the percent of students have a higher score than hers is 30.85%.