Statistics And Probability Question 465
Question: If the mean of the numbers $ 27+x $ , $ 31+x $ , $ 89+x $ , $ 107+x,156+x $ is 82, then the mean of $ 130+x,126+x,68+x,50+x,1+x $ is
[Pb. CET 1989; Kurukshetra CEE 2000; Kerala (Engg.) 2001]
Options:
A) 75
B) 157
C) 82
D) 80
Show Answer
Answer:
Correct Answer: A
Solution:
Given, $ 82=\frac{(27+x)+(31+x)+(89+x)+(107+x)+(156+x)}{5} $
$ 82\times 5=410+5x $
$ 410-410=5x $
$ x=0 $
Required mean is, $ \bar{x}=\frac{130+x+126+x+68+x+50+x+1+x}{5} $ $ \bar{x}=\frac{375+5x}{5} $ $ =\frac{375+0}{5} $ $ =\frac{375}{5} $ = 75.
BETA
