Question

a box has 6 red and 3 black marbles. one marble is selected at random. find the probability that the selected marble is : (a) red (b) black​

Answer 1

Order doesn't matter, so let’s choose red first, then blue. The probability of the first being red is 6/10 AND then the probability of the second being red is 5/9 AND then the probability of the third being blue is 4/8. AND means to multiply.

Answer 2

total marbles = 3+6. =9

probability of red marble is 6/9. =2/3

probability of black marble =3/9. = 1/3