Question

Linh has obtained scores of 82, 79, and 75 on her midterm algebra exams. If the final exam counts twice as much as a midterm, what score must she make on her final exam to get an average score of 80? (Assume that the maximum possible score on each test is 100.)

Answer 1

She must make a score of 42 in the final exam to obtain an average of 80.

Explanation:

Hi there!

Let x be the score of the final exam, the equation will be as follows (remember that the score of the final counts double):

(82 + 79 + 75 + 2x)/4 = 80

Let´s solve the equation for x multiplying each side of the equation be 4:

82 + 79 +75 + 2x = 320

Substract 82, 79 and 75 to both sides of the equation:

2x = 320 - 82 - 79 -75

2x = 84

x = 84/2

x = 42

She must make a score of 42 in the final exam to obtain an average of 80.

Have a nice day!