Papers = 90 (0.40)
Tests = 80 (0.40)
Final exam minimum score required = x (0.20)
Average = 87
For the minimum score, linear inequality is involved in the problem. Use symbol ≥ .
Weighted Average Equation:
[(90)(0.40)] + [(80)(0.40)] + [(0.20) (x)] ≥ 87
36 + 32 + 0.20x ≥ 87
68 + 0.20x ≥ 87
0.20x ≥ 87 - 68
0.20x ≥ 19
0.20x ÷ 0.20 ≥ 19 ÷ 0.20
x ≥ 95
Solution = {x/x ≥ 95} ; interval = [95, ⁺∞)
ANSWER: The student must earn a minimum value, or score of at least, 95 in the final exam to get a B⁺ equivalent to 87.
Check:
36 + 32 + (0.20)(95) ≥ 87
68 + 19 ≥ 87
87 ≥ 87