Ajar contains 4 red marbles and 8 blue marbles. a marble is drawn from the jar. what is the probability that a red marble is drawn?

4 red marbles. 
8 blue marbles.

Now lets add these two to find out the total. 

4 + 8 = 12

So, 12 marbles in total.

4 red marbles so our fraction would look like this:-



Lets simplify:- 



So, our answer in simplest form is:- .

Hope i helped ya!!