Answer:
Mean = 90.67
Step-by-step explanation:
The three consecutive month periods with the highest monthly cell phone bills are:
May, June, July
May, x₅ = $95
June, x₆ = $87
July, x₇ = $90
The mean of the three consecutive month periods with the highest mean of the year is calculated below
![\begin{gathered} Mean=(\sum x_(567))/(3) \\ \\ Mean=(x_5+x_6+x_7)/(3) \\ \\ Mean=(95+87+90)/(3) \\ \\ Mean=(272)/(3) \\ \\ Mean=90.67 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/p33migh7tyaaxglrs54kpxz68ium9m6kwc.png)