optimazation , please solve with clear font !

Q8: Sarah is about to take a math test that contains short answer questions worth 4 points each and word problems worth 7 points each. She is required to do at least 5 short answer problems, but no more than 10. She must do at least 3 word problems, but no more than 10. She is required to do at least 9 problems of types, but no more than 18. Formulate this problem to maximize her score