b- 3/20. first, add up the number of balls in each urn.
urn 1- 10
urn 2- 8
then, make a fraction where the numerator is the number of blue balls in the urn and the denominator is the total number of balls
urn 1- 6/10 (simplified to 3/5)
urn 2- 2/8 (simplified to 1/4)
finally, multiply your two probabilities and simplify
1/4*3/5=3/20