Answer: The last score must be 92%
Step-by-step explanation: To find the average, you add all the terms, then divide by the number of terms.
- 86 = [tex]\frac{90 + 76 + x}{3}[/tex]
- 258 = 90 + 76 + x (multiple both sides by 3)
- 258 = 166 + x (combine like terms)
- 92 = x (subtract 166 from both sides)