Answer:

Step-by-step explanation:
Urn U1: 3 red and 2 yellow marbles, in total 5 marbles.
The probability to select red marble is
Urn U2: 3 red and 7 yellow marbles, in total 10 marbles.
The probability to select red marble is
Urn U1: 1 red and 4 yellow marbles, in total 5 marbles.
The probability to select red marble is
The probability to choose each urn is the same and is equal to 
Thus, the probability that the marble is red is
