Lynn072
contestada

There are 3 black marbles and 4 red marbles in a bag.
What is the probability you will pick two black marbles out of the bag without replacing the first one chosen?


A) 6/8

B) 9/49

C) 5/13

D) 1/7

Respuesta :

gmany
3 + 4 = 7 all marables in bag
The probability that the first marable is black
[tex]P(A_1)=\dfrac{3}{7}[/tex]
The probability that the second marable is black too
[tex]P(A_2)=\dfrac{2}{6}=\dfrac{1}{3}[/tex]
Together:
[tex]P(A)=P(A_1)\cdot P(A_2)=\dfrac{3}{7}\cdot\dfrac{1}{3}=\dfrac{1}{7}\to D[/tex]