A survey of 100 doctors revealed that 2 out of every 5 doctors recommended Brand M deodorant. Based on these results, how many d
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Answer:
The probability that A selects the first red ball is 0.5833.
Step-by-step explanation:
Given : An urn contains 3 red and 7 black balls. Players A and B take turns (A goes first) withdrawing balls from the urn consecutively.
To find : What is the probability that A selects the first red ball?
Solution :
A wins if the first red ball is drawn 1st,3rd,5th or 7th.
A red ball drawn first, there are places in which the other 2 red balls can be placed.
A red ball drawn third, there are places in which the other 2 red balls can be placed.
A red ball drawn fifth, there are places in which the other 2 red balls can be placed.
A red ball drawn seventh, there are places in which the other 2 red balls can be placed.
The total number of total event is
The probability that A selects the first red ball is
-16t^2+400=0
16t^2=400
take square root on both sides.
4t=20
t=20/4
t=5