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Pats final exam has 4 times the weight of her weekly exams. If she had 10 weekly exams with a weight of 1 each and an average of 92, and her overall weighted average was 88, what was her grade on the final exam?

Respuesta :

Since the total of weight of an exam is 100 and the final exam is 4 times the weekly exam  
X + 4x = 100 %
5x = 100 %
X = 20%
4x = 80%  


Weighted ave = 0.2( ave weekly exam) + 0.8(final exam 88 = 0.2(92) + 0.8(final exam)
Solve for the final exam
Final exam = 87

Answer: 78

Step-by-step explanation: For the weekly exams, we have  x /10  = 92, x = 920. Assume that the final score is y with weight 4. Since the overall weighted average is the sum of the weighted scores divided by the sum of the weights, then  920 + 4y  / 14  = 88, 920 + 4y = 1232, 4y = 312, y = 78.