Answer:
The required inequality is
.
Jhon can buy at most 5 books.
Explanation:
Consider the provided information.
Part(A)
Let b represent the number of books John buys.
He wants at least $10 in his savings account which means if we subtract the cost of books from $40 we have at least $10 left.
![40-6b\leq 10](https://img.qammunity.org/2022/formulas/mathematics/high-school/3ybnapwjmv2zt9llshgsx32kqtbr0c26g4.png)
The required inequality is
.
Part(B)
![40-6b\leq 10](https://img.qammunity.org/2022/formulas/mathematics/high-school/3ybnapwjmv2zt9llshgsx32kqtbr0c26g4.png)
![-6b\leq 10-40](https://img.qammunity.org/2022/formulas/mathematics/high-school/95adqwxdfmrhvz3j4k6opwo3t8oxo651mi.png)
![b \leq(30)/(6)](https://img.qammunity.org/2022/formulas/mathematics/high-school/wc2ii1pkkzewafgjdfkxq8o7juxu150z8p.png)
![b\leq 5](https://img.qammunity.org/2022/formulas/mathematics/high-school/r8hy4nowb29obgapnkzvtycscggz99qi9t.png)
Part(C): Jhon can buy at most 5 books.