Why this is a error

Question

I'm making a test result using oop in php if $nilai is greater than or equal to 65 and less or equal to 100 then the $hasil variable contains a pass string if not then the $hasil variable contains a failed string. but when I run it an error occurs and I don't know which error and why it can be an error. help me finish this, thank you.
https://code.sololearn.com/wUODWh7K6Ehn/?ref=app

Answer 1

https://code.sololearn.com/wD7mOIBklmaz/?ref=app

Answer 2

Solved