The Answer would be x=72. Why? Because 
is your %. You Cross multiply 240 * 30 = 100x
240 time 30 = 7200. you want x to be alone so you do 7200 divided by 100 equaling 72. So you get x=72.
240 time 30 = 7200. you want x to be alone so you do 7200 divided by 100 equaling 72. So you get x=72.