Fact assumption table
Try your script without the tags. It's possible that Apache automatically runs the script through PHP only and not HTML with PHP. This will mean that it sees echo 'Hello' only if it understands the rest of the code. If it is only running PHP it might not understand the tags and just print out the whole thing. There's a slim chance but try it out just in case. See if that will help.
Your web browser may not support PHP. You should check what web browser you're using. If you're using Midori, it might not support it. Try doing this on a different device and accessing another browser like Google Chrome.
Make sure that your file extension is not .txt - This might be the reason for it not seeing and not compiling your code.
Taken from this stackoverflow question
Make sure that Apache's httpd.conf file has the PHP MIME type in it. This should be something like AddType application/x-httpd-php .php . This tells Apache to run .php files as PHP.
IF ALL ELSE FAILS, TRY TO USE PHP WITH A DIFFERENT COMPILER.
Possible links that may help:
Another stack overflow question
If your HTTPS.config file is wrong
I hope this helps.