Answer:
First question:0
Second question:2/15
Explanation:
First:
Total of marbles=10
since there is no blue the probability is 0, since black is 3. then prob= number of black/total number of marbles. =3/10
therefore 0*3/10 =0
second:
probability of red is 4/10
since the first marble wasn't returned,the total number of marbles=9
therefore probability if the second red marble is =3/9 =1/3
probability of first marble *probability of second marble
(4/10)*(1/3) =(4/30)= 2/15