A bag contains pour red marbles, 5 blue marbles,
2 yellow marbles. Two marbles
first replaced before the second
drawn
what is probability that they
same colour?
Answers
Answered by
1
Answer:
irst draw:
You have
15
marbles in total and
7
purple ones.
Thus, the probability for the first marble to be purple is
P
(
1
st marble is purple
)
=
7
15
.
Second draw:
Since you have put the first marble back in the bag, you still have
15
marbles in total. However, there are only
3
red ones.
Thus, the probability to draw a red marble is
P
(
2
nd marble is red
)
=
3
15
As these two events are independent, you just need to multiply the two probabilities:
P
(
1
st marble is purple and
2
nd marble is red
)
=
P
(
1
st marble is purple
)
⋅
P
(
2
nd marble is red
)
=
7
15
⋅
3
15
=
7
15
⋅
1
5
=
7
75
≈
0.0933
≈
9.33
%
Step-by-step explanation:
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