Given 3 scores of 84, 84, 84:
what should be score number 4
in order to attain an average score of 87?
Setup Average Equation:
| Average = | Sum of our 3 numbers + unknown score of x |
| Total Numbers |
| 87 = | 84 + 84 + 84 + x |
| 4 |
Cross Multiply
84 + 84 + 84 + x = 87 x 4
x + 252 = 348
Subtract 252 from both sides of the equation to isolate x:
x + 252 - 252 = 348 - 252
Final Answer
x = 96
