Answer: His usual average = 28.
Step-by-step explanation:
Let x = usual average at the basketball game tonight.
As per given,
[tex]\dfrac{x}{2}+10=24[/tex]
Subtract 10 from both sides , we get
[tex]\dfrac{x}{2}+10-10=24-10\\\\\Rightarrow\ \dfrac{x}{2}=14\\\\\Rightarrow\ x=14\times2=28[/tex]
Hence, his usual average = 28.