A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn

Question

A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn at random without replacement . What is the probability that one ball is white?

A. 2/35
B. 10/21
C. 1/2
D. 3/4
E. 4/5

preetamsaha · Answer

A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn at random without replacement . What is the probability that one ball is white?

at first drawn W , at second drawn G
Probability = 5/15*6/14 (without replacement)

at first drawn W , at second drawn B
Probability = 5/15*4/14 (without replacement)

at first drawn B , at second drawn W
Probability = 4/15*5/14 (without replacement)

at first drawn G , at second drawn W
Probability = 6/15*5/14 (without replacement)

So, required probability = (30+20+20+30)/15*14 = 10/21

correct answer B

ArunSharma12 · Answer

number of ways to take 2 balls =  15_C_2 
number of ways to take one white ball =  5_C_1 	imes 10_C_1 
probability =  \frac{5 	imes 10 	imes 2}{ 15 	imes 14}  =  \frac{10}{21} 
Ans: B

Kinshook · Answer

Given: A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn at random without replacement . 
Asked: What is the probability that one ball is white?

Total balls = 15 
Total ways to draw 2 balls out of 15 =  ^{15}C_2 = 105

Number of ways so that one balls is white =  ^5C_1 * ^{10}C_1 = 5 * 10 = 50

Probability =  \frac{50 }{105} = \frac{10}{21}

IMO B

Kritisood · Answer

hi, is this approach right?

first white = 5/15
second any other color = 10/14
total prob: 5/15*10/14*2

Bunuel · Answer

The answer will be revealed on Saturday but  yes, it's a correct approach and answer .

rishab0507 · Answer

White ball can be drawn Frist time or 2nd time: 
Probability if 1st ball is white : 5/15 * 10/14 (10/14 is red + blue balls / balance no of balls in bag as its w/o replacement) ---------------------- 1
Probability if 2nd ball is white : 10/15 *5/14 ---------------- 2
Adding 1 and 2
10/42 +10/42 = 20/42 => 10/21

IMO B

A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn

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A bag contains 4 blue, 5 white and 6 green balls. Two balls are drawn

Prep Toolkit

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