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PS - median

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PS - median

by Xbond » Fri Sep 11, 2009 10:53 am
Hi there,

Could you give me your ELEGANT, QUICK, and EFFICIENT method to resolve (with these concepts and with finding the solution).


A list of measurements in increasing order is 4, 5, 6, 8, 10, and x. If the median of these measurements
is 6/7 times their arithmetic mean, what is the value of x ?

a)16
b)15
c)14
d)13
e)12
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by Nermal » Fri Sep 11, 2009 12:46 pm
IMO A (16)

median is 7

arithmetic mean is median/(6/7)=7/(6/7)=7*(7/6)=49/6

(4+5+6+8+10+x)/6=49/6
(33+x)/6=49/6
33+x=49
x=16
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by Xbond » Mon Sep 14, 2009 12:50 am
many thks

OA is A
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by fruti_yum » Tue Sep 15, 2009 11:17 am
Nermal wrote:IMO A (16)

median is 7

arithmetic mean is median/(6/7)=7/(6/7)=7*(7/6)=49/6

(4+5+6+8+10+x)/6=49/6
(33+x)/6=49/6
33+x=49
x=16
Nermal how did u know that median was 7?
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by Nermal » Wed Sep 16, 2009 1:53 am
You have six numbers in increasing order and the median is always the middle number. If there is, as it is here, an even number of numbers you have to add the third and the fourth number and divide this sum by two:
(6+8)/2=7
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