Math, asked by Ishita, 1 year ago

A bag contains  white,  red  and  black  balls.  A  ball  is  drawn  at  random  from  the  bag.  The  probability of  getting  a  white  ball  is 3/ 10   and that  of black  ball  is 2/ 5 .  (a)  Find  the  probability  of  getting  a  red  ball.  (b)  If  the  bag  contains  20  black  balls,  then  find  the  total  number  of  balls. ​

Answers

Answered by harshjr7
1

let W be the white balls

let R be the red balls

let B be the black balls

P(W) + P(B)+ P(R) = 1 (the sum of all probablities is 1)

3/10 + 2/5 + P(R) =1

15+20/50 +P(R)=1

35/50 +P(R) =1

P(R)= 1- 7/10

P(R)= 3/10

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