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# A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb

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A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb  [#permalink]

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22 May 2018, 10:50
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Difficulty:

15% (low)

Question Stats:

77% (00:56) correct 23% (01:23) wrong based on 96 sessions

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A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random. What is the probability that Alpha and Navarro both select white marbles.

1. 4/25

2. 9/25

3. 2/5

4. 3/5

5. 4/5

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Re: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb  [#permalink]

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22 May 2018, 11:01
Top Contributor
QZ wrote:
A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random. What is the probability that Alpha and Navarro both select white marbles.

1. 4/25

2. 9/25

3. 2/5

4. 3/5

5. 4/5

P(both are white) = P(1st marble is white AND 2nd marble is white
= P(1st marble is white) x P(2nd marble is white)
= 4/10 x 4/10
= 16/100
= 4/25

Cheers,
Brent
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Re: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb  [#permalink]

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01 Jun 2018, 23:46
QZ wrote:
A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random. What is the probability that Alpha and Navarro both select white marbles.

1. 4/25

2. 9/25

3. 2/5

4. 3/5

5. 4/5

Total marbles = 10

White marbles = 4

Required outcome = 4/10 * 4/10

4/25

(A)

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Re: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb  [#permalink]

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11 Aug 2019, 20:05
1
AkshdeepS wrote:
A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random. What is the probability that Alpha and Navarro both select white marbles.

1. 4/25

2. 9/25

3. 2/5

4. 3/5

5. 4/5

The probability that both select white marbles is 4/10 x 4/10 = 2/5 x 2/5 = 4/25.

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Re: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb  [#permalink]

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11 Aug 2019, 21:54
AkshdeepS wrote:
A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random. What is the probability that Alpha and Navarro both select white marbles.

1. 4/25

2. 9/25

3. 2/5

4. 3/5

5. 4/5

Given: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marble from the bag at random, records its color and places it back in the bag. Then, Navarro selects a marble from the bag at random.

Asked: What is the probability that Alpha and Navarro both select white marbles.

Probability that Alpha selects white marbles = $$\frac{4}{10}$$
Probability that Navarro selects white marbles = $$\frac{4}{10}$$

Probability that both select white marbles $$= \frac{4}{10} * \frac{4}{10} = \frac{2}{5} * \frac{2}{5} = \frac{4}{25}$$

IMO A
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Re: A bag contains 6 red marbles and 4 white marbles. Alpha selects a marb   [#permalink] 11 Aug 2019, 21:54
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