Question

In a given course a student receives preliminary examination grades of 81, 85, and 95. The final examination is weighed for one-third and the average of the preliminary grades is weighed as 2/3 of the final grade. What should the final examination grade be for a semester average of 90?
99
96
93
88
87

Answer 1

Answer:

B. 96

Step-by-step explanation:

Let x represent score of final third exam.

We have been given that in a given course a student receives preliminary examination grades of 81, 85, and 95.

Let us find average of preliminary scores.

$\frac{81+85+95}{3}=\frac{261}{3}=87$

We have been given that the final examination is weighed for one-third and the average of the preliminary grades is weighed as 2/3 of the final grade. This means that final grade is equally weighed into 3 parts. The two parts are 87 each and third part is x.

Using our given information, we can set an equation as:

$\frac{87+87+x}{3}=90$

$\frac{174+x}{3}=90$

$\frac{174+x}{3}*3=90*3$

$174+x=270$

$174-174+x=270-174$

$x=96$

Therefore, the final examination grade should be 96 for a semester average of 90.