There are four spots in total in the circle. Two of them are blue. Therefore, the probability of it lading on blue is 2/4, which simplifies to 1/2. Hope this helped.
If Jon spins the spinner 200 times, it will land on the blue about 100 times. This is because of all the colors on the circle, blue takes up half of the circle. Whereas other colors only take up a quarter. 200/2=100!
