Hey everyone. I would like to know is it possible to have a page on my site that has a form that allows people to select an answer from a multiple choice question, input their paypal details and press the submit button which will automatically charge them a certain amount and send their question answer along with the payment?

Yes it is.

Cool, am I going to need to adapt one of their merchant tools, or is there a better way of doing it?

Probably much quicker to write something.

Have a basic form with the options and fields for the user to add their info as required, submit this to some server side code that builds the PayPal submission form and shows the user what they are sending and a "confirm" button to send the form.