On the last three physics exams a student scored 88​, 87​, and 89. What score must the student earn on the next exam to have an average of at least 90

Question

On the last three physics exams a student scored 88, 87, and 89. What score must the student earn on the next exam to have an average of at least 90

Answer 1

(88 + 87 + 89 + x)/4 >= 90

 

Solve for x.

Answer 2

To get an average of 90 the student needs a total of 360 point (4 x 90)

The student has 264.

How many more (on the last test) are needed?