Tuesday, 1 May 2018

PROBABILITY 2


A school survey found that 4 out of 10 students like pizza. If three students are chosen at random with replacement, what is the probability that all three students like pizza?

Solution

THIS IS AN INDEPENDENT EVENT. THE 1ST CHOICE HAS NO ANY EFECT FOR THE 2ND OR 3RD.
 
P(student 1 likes pizza)
 = 
 4 

10


P(student 2 likes pizza)
 = 
 4 

10


P(student 3 likes pizza)
 = 
 4 

10


P(student 1 and student 2 and student 3 like pizza)
 = 
 4 
 · 
 4 
 · 
 4 
 = 
 8 
10
10
10
125

Hence probability that all three students like pizza is 8/125 .

TRY THIS………..


A school survey found that 3 out of 5 students like coffee. If three students are chosen at random with replacement, what is the probability that all three students like coffee? 

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