We're trying to find out how many two point questions, and how many four point questions there are. So it's probably a good choice to choose these as our variables. Let's call the the number of two point questions and the number of four point questions .

Now let's look at the information we've been given by the problem.

worth 100 points

So twice the number of two point questions, plus four times the number of four point questions equals 100.

containing 40 questions

So the number of two point questions, plus the number of four point questions equals 40.

Using the super duper 2x2 linear simultaneous equation solver, this is my first time using it btw. We get:

Always remember to substitute in and check the answer is right.

Hope that helps

Kev