anurag16 wrote:

X is a set containing 7 different numbers. Y is the set containing 6 different positive numbers all of which are members of set X. Is the mean of X equal to the mean of Y?

a) Range of X is greater than range of Y

b) Sum of all the numbers in set X< Sum of all the numbers in set Y

Hi..

If all 7 numbers are different and 6 of them have a certain MEAN, M..

This would be EQUAL to mean of 7 numbers ONLY when 7th number itself is EQUAL to M...

Let's see the statements...

a) Range of X is greater than range of Y

This means the 7th number is either greater than or less than the 6 numbers in set Y..

So the 7 number cannot be EQUAL to mean of 6 numbers..

Ans is NOSufficient

b) Sum of all the numbers in set X< Sum of all the numbers in set Y

Clearly a lower number /7 will be less than greater number/6..

Clearly mean of Y>mean of X..

Ans is again NOSufficient

D

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor