Answer:
Felix's third test score must be greater than 94
Explanation:
Felix scores on Sociology 212 tests:
1st test - 52
2nd test - 64
3rd test - x
Find the average of Felix's scores:
![\text{Average}=\frac{\text{The sum of all scores}}{\text{The total number of scores}}\\ \\\text{Average}=(52+64+x)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/q0vdtjvyp4wb6294mbsknc3uciod1v3ue6.png)
An average of the three test must be above 70, this means
![\text{Average}>70\\ \\(52+64+x)/(3)>70](https://img.qammunity.org/2020/formulas/mathematics/middle-school/91peofjhts41cp1v9yako80d4dbf2pehr7.png)
Solve this inequality. First, multiply it by 3:
![52+64+x>210\\ \\x>210-52-64\\ \\x>94](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yhrcxiswdgt09wztsp0apavrbzx57c21wx.png)