Abag contains 5 purple marbles and 5 orange marbles. rahul reaches into the bag and draws one marble without looking. then he replaces the marble and repeats the experiment. if he repeats the experiment 120 times, how many times should he expect to pull out an orange marble? someone me i need to finish this soon

First compute the probability of getting an orange marble. 
Number of favorable possibilities: 5.
Number of all the possibilities: 10.
So the probability of getting an orange marble is: 5/10=1/2.
Since the above probability is 50%, then multiply by the 120 experiment in order to get the number of time we expect an orange marble:

60 times.