a bag has 5 red marbles, 6 blue marbles and 4 black marbles. what is the probability of a blue marble, replacing it, and then picking a black marble? 8/754/451/9

There are 15 total marbles in the bag, of which 6 are blue nd 4 are black.

The probability of pulling a blue marble from the full bag is  6/15 .

The probability of pulling a black marble from the full bag is  4/15 .

The probability of both events happening is

             (6/15) x (4/15)  =  24/225 = 8/75

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.