Hey there! We receieved your request
Stay Tuned as we are going to contact you within 1 Hour
One of our academic counsellors will contact you within 1 working day.
Click to Chat
1800-5470-145
+91 7353221155
Use Coupon: CART20 and get 20% off on all online Study Material
Complete Your Registration (Step 2 of 2 )
Sit and relax as our customer representative will contact you within 1 business day
OTP to be sent to Change
A box contains 24 identical balls of which 12 are black and 12 are white.The balls are drawn at random from the box one at a time with replacement.The probability that a white ball is drawn for the fourth time on the seventh draw is
Ans=> 5/32
Please explain how this answer came.
The explanation should be detailed as i have found this question on many books also but not understood.
think of it this way:
the fourth draw is gonna happen at the 7th draw...
this means 3 draws have already occured in the previous 6
this means it COULD HAVE OCCURED IN 6C3 ways= 20 ways
and total ways or possibilites(sample space) for that was 2^6 (because the are only 2 colours and either white or black, ie 1+1=2 and 6draws therefore 2^6)
"AND"the seventh ball would be white has probability 12/24 = 1/2...
so total probability is
(20/2^6)*(1/2) =5/32
i hope u understood :)
if u dint feel free to ask again
Get your questions answered by the expert for free
You will get reply from our expert in sometime.
We will notify you when Our expert answers your question. To View your Question
Win Gift vouchers upto Rs 500/-
Register Yourself for a FREE Demo Class by Top IITians & Medical Experts Today !