Problema Solution

a student's grade in a course is the average of 4 test grades and a final exam that is worth three times as much as each test. suppose a student has test grades of 89,88,78, and 94. write an equation to model this situation where x is the student's grade on the final exam and Y is the student's average for the course.

then find the score they will need to receive on their final exam if they want to have a grade of 88 for the course.

Answer provided by our tutors

Alright. So he took 4 tests already and the final is worth as 3 regular tests. The equation would look like this for the average for the course. 

 

Y= (89+88+78+94+3X)/7

 

If you want the average for the course to be 88, just let Y=88. 

Multiple both sides by 7 and you should get 

616=349+3x

Subtract 349 from both sides.

267=3x

Divide by 3.

x=89

 

89 is the grade he needs to get on the final in order to get an 88 for the course.