Solve the problem.
-Ashley's grades on her first 3 exams are 85, 78, and 80. An average greater than or equal to 80 and less than 90 will result in a final grade of B. What range of grades on Ashley's fourth and final exam will result in a final
Grade of B? The maximum grade is 100.
A) $77 \leq x \leq 100$
B) $67 \leq x \leq 90$
C) $77 \leq x

Question

Solve the problem.
-Ashley's grades on her first 3 exams are 85, 78, and 80. An average greater than or equal to 80 and less than 90 will result in a final grade of B. What range of grades on Ashley's fourth and final exam will result in a final
Grade of B? The maximum grade is 100.
A) $77 \leq x \leq 100$
B) $67 \leq x \leq 90$
C) $77 \leq x < 117$
D)Impossible to get a B.

Quizplus · Accepted Answer

To achieve a final grade of B, Ashley's average must be $\geq 80$ and $< 90$. The sum of her first three exam grades is $85 + 78 + 80 = 243$. For an average of 80, the total of all four exams must be at least $4 \times 80 = 320$. Thus, the minimum score for the fourth exam is $320 - 243 = 77$. For an average below 90, the total must be $4 \times 90 = 360$, giving a maximum possible score of $360 - 243 = 117$. However, since the maximum grade is 100, the range is $77 \leq x \leq 100$.

Solve the Problem 77≤x≤10077 \leq x \leq 10077≤x≤100 B) 67≤x≤9067 \leq x \leq 9067≤x≤90

Solve the Problem $77 \leq x \leq 100$ B) $67 \leq x \leq 90$