DS-Plz. help

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 458
Joined: Sun Aug 31, 2008 10:44 am
Thanked: 3 times
Followed by:1 members

DS-Plz. help

by gmat009 » Fri Oct 10, 2008 9:14 am
What is value of (x-y)^4
a) The product of x and y is 7
b) x and y are integers

Master | Next Rank: 500 Posts
Posts: 133
Joined: Sat Dec 29, 2007 2:43 am
Thanked: 12 times

by raju232007 » Fri Oct 10, 2008 9:40 am
statement 1:

the product of x and y is 7
In the question it is not mentioned whether x& y are integers or fractions
if x and y are integers x=7,y=1.......... xy=7
if x and y are fractions x=7/4,y=4.......xy=7

Insufficient

statement 2:

x an y are integers
The values of x or y aren't mentioned
Insufficient

Combining both the statements we get four possibilities
x=7,y=1
x=1,y=7
x=-1,y=-7
x=-7,y=-1

When both x and y are positive (x-y)^4=(7-1)^4=6^4=1296
When both x and y are negative (x-y)^4=(-1+7)^4=6^4=1296

Hence the ans should be C..Let me know if you have any doubts

Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Fri Oct 10, 2008 9:46 am
same here imo C