Good evening
The absolute value has the following property:
[tex]|x|\leq a\iff -a\leq x\leq a[/tex]
Apllying:
[tex]|T-55| \leq 10 \iff -10\leq T - 55 \leq 10\\ \\ -10 + 55 \leq T -55 + 55 \leq 10 + 55\\ \\ \boxed{45\leq T \leq 65}[/tex]
The average temperature range is between 45 and 65 degrees.
