Probability that next marble is not red is 0.75
Solution:
Given that bag of marbles contains blue (B), red (R), yellow (Y), and green (G) marbles.
A marble is drawn from the bag, recorded, and then placed back in the bag. To find: the probability the next marble is NOT red
The probability of an event is given as:

Let us first find the probability of getting red marble
Total number of possible outcomes = blue + red + yellow + green
Total number of possible outcomes = 4
Favorable outcome = getting red marble
Number of favorable outcomes = 1

Finding probability that next marble is NOT red:
P( NOT R) = 1 - P(R)

Thus probability that next marble is not red is 0.75