There are 7 balls in a box 3 black and 4 red a ball will be drawn and not replacecd then a second ball wil lbe drawn what is the chances it will be a black ball and then red ball?

The probability of getting on the first draw a black ball is: P(B1) =

3/7.

The probability of getting a red ball given the event of drawing a black ball on the

first draw is: P(R2│B1) =

4/6.

The probability of drawing a black ball on the first draw and a red ball on the second draw is: P(B1UR2) =

P(B1)∙P(R

2│B1) =

(3/7)∙(4/6) =

0.2857... ~ 0.286 ~ ~ 28.6%