Question

To get a B in a course you must have an average of atleast 80 points for 4 test of 100 points each. For the first 3 test your score are 77, 84,and 81. What must you score on the fourth test to earn an 80% average for the course

Answer 1

78 :D

so let's pretend that the 4th test is x and work through it that way :)

Explanation:

(77+84+81+x)/4=80

77+84+81+x=320

242+x=320

x=78