Recall that to find the theoretical probability we use the following expression:
[tex]\frac{\text{favorable cases}}{total\text{ cases}}.[/tex]Since the jar contains 20 yellow marbles, 55 green marbles, and 25 purple marbles, then the jar contains 20+55+25=100 marbles. Therefore, the theoretical probability of picking a green or a yellow marble is:
[tex]\frac{20+55}{100}=\frac{75}{100}=0.75.[/tex]The above decimal number written as a percentage is 75%.
Answer: Option D.
