Answer:
![80\leq x\leq 70](https://img.qammunity.org/2019/formulas/mathematics/high-school/n66zb77t5aw5tuwqxqrmyuol2b695szt8l.png)
Explanation:
Mr. Venn knows that 60% of his students will score no more than 5 points above or below the class average, 75%, on the test.
Means the greater marks can be up to 80 and lowest marks can be up to 70.
So, the inequality that represents the test scores of 60% of his students is :
![80\leq x\leq 70](https://img.qammunity.org/2019/formulas/mathematics/high-school/n66zb77t5aw5tuwqxqrmyuol2b695szt8l.png)