Given 2 scores of 88, 92:
what should be score number 3
in order to attain an average score of 90?
Setup Average Equation:
| Average = | Sum of our 2 numbers + unknown score of x |
| Total Numbers |
| 90 = | 88 + 92 + x |
| 3 |
Cross Multiply
88 + 92 + x = 90 x 3
x + 180 = 270
Subtract 180 from both sides of the equation to isolate x:
x + 180 - 180 = 270 - 180
Final Answer
x = 90
