Math, asked by arshveer4185, 1 year ago

One beg contains 4 red balls and 3 blue balls and second beg contains 3 red and 5 blue balls . One ball is drawn at random from the first bag and put unseen in the second bag . What is the probability that a ball now drawn from the second bag is blue ?

Answers

Answered by Anonymous
0

There are two ways that you can get a blue ball from the second bag

These are

Red from the first followed by blue from the second

Blue from the first followed by blue from the second

The probability that you draw a red from the first is 4/7 (7 balls in total and 4 are red)

Now assuming you have drawn a red when placed in the second bag there are now 4 red and 5 blue in the second bag. Therefore the probability that you draw blue given that a red was placed in it = 5/9, ie 5 blues out of 9 in total

Therefore P(red then blue) = 4/7 * 5/9 = 20/63

Now The probability that you draw a BLUE from the first is 3/7 (7 balls in total and 3 are blue)

Now assuming you have drawn a blue, when placed in the second bag there are now 3 red and 6 blue in the second bag. Therefore the probability that you draw blue given that a blue was placed in it = 6/9, ie 6 blues out of 9 in total

Therefore P(blue then blue) = 3/7 * 6/9 = 18/63

Therefore the probability that you draw a blue ball from the second bag

= P(red then blue) + P(blue then blue)

= 20/63 + 18/63

= 38/63

Answer = 38/63.

FYI the only other solutions are

Red from the first followed by red from the second = 4/7 * 4/9 = 16/63

Blue from the first followed by red from the second = 3/7 * 3/9 = 9/63

Check

Red + Blue = 20/63

Blue + Blue = 18/63

Red + Red = 16/63

Blue + Red = 9/63

Total = 63/63

Answered by mgssksinha
2

Step-by-step explanation:

Total balls in first bag = 4 red and 3 blue

second bag = 3 red and 5 blue

Total balls in second bag = 8

ATQ

One ball is dropped from first to second

So,

Total balls in second bag now = 9

Probability that it is blue

5/9

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