The operators '*' and '+' operate only on the numbers 0 and 1 as defined in the table (please see attachment). If x*y=1 which one of the following does (x*y)+x equal?
(A) -2
(B) -1
(C) 0
(D) 1
(E) 2
OA is D
Source: Nova's GMAT DS Prep course, p.119
DS: Defined functions
This topic has expert replies
- ikaplan
- Master | Next Rank: 500 Posts
- Posts: 181
- Joined: Fri Sep 04, 2009 12:06 pm
- Thanked: 17 times
- Followed by:1 members
- Attachments
-
- DS Defined Functions.doc
- (25.5 KiB) Downloaded 113 times
"Commitment is more than just wishing for the right conditions. Commitment is working with what you have."
- force5
- Legendary Member
- Posts: 582
- Joined: Tue Mar 08, 2011 12:48 am
- Thanked: 61 times
- Followed by:6 members
- GMAT Score:740
its more like Boolean. 1 is for true and 0 is false. if any one (x or y) has 1 then true is returned.
since x*y is 1 that means either x has 1 or y has 1 or both have 1.
hence the sum with x will always yield a 1 (true)
since x*y is 1 that means either x has 1 or y has 1 or both have 1.
hence the sum with x will always yield a 1 (true)
- [email protected]
- Legendary Member
- Posts: 934
- Joined: Tue Nov 09, 2010 5:16 am
- Location: AAMCHI MUMBAI LOCAL
- Thanked: 63 times
- Followed by:14 members
Confused between D and E. Could somebody please help in this question.
Eg: x = 1 and y = 1. as (x X Y) = 1 also see the attachment.
Now see the other things...
(x X y) + x = 1 + 1 = 2. This is one solution.
the other solution is given by the other people.
The other solution is: The question says that '*' and '+' are operational only when they both are 0 and 1 otherwise the values given in the table chart will be applied.
So does that mean that the operation (x X Y) + x will not be operational as both the numbers are 1 and 1 and the operational sign is '+'. And so we chose the answer as 1 and not 2.
Then what about the chart where a = 0 and b = 0, the final answer given is also not operational so how come the final answer comes out to be the same as when the sign would be operational.
Tricky and just a few doubts. Help needed...
Eg: x = 1 and y = 1. as (x X Y) = 1 also see the attachment.
Now see the other things...
(x X y) + x = 1 + 1 = 2. This is one solution.
the other solution is given by the other people.
The other solution is: The question says that '*' and '+' are operational only when they both are 0 and 1 otherwise the values given in the table chart will be applied.
So does that mean that the operation (x X Y) + x will not be operational as both the numbers are 1 and 1 and the operational sign is '+'. And so we chose the answer as 1 and not 2.
Then what about the chart where a = 0 and b = 0, the final answer given is also not operational so how come the final answer comes out to be the same as when the sign would be operational.
Tricky and just a few doubts. Help needed...
IT IS TIME TO BEAT THE GMAT
LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
- rijul007
- Legendary Member
- Posts: 588
- Joined: Sun Oct 16, 2011 9:42 am
- Location: New Delhi, India
- Thanked: 130 times
- Followed by:9 members
- GMAT Score:720
for the operations refer the given chart...[email protected] wrote:Confused between D and E. Could somebody please help in this question.
Eg: x = 1 and y = 1. as (x X Y) = 1 also see the attachment.
Now see the other things...
(x X y) + x = 1 + 1 = 2. This is one solution.
the other solution is given by the other people.
The other solution is: The question says that '*' and '+' are operational only when they both are 0 and 1 otherwise the values given in the table chart will be applied.
So does that mean that the operation (x X Y) + x will not be operational as both the numbers are 1 and 1 and the operational sign is '+'. And so we chose the answer as 1 and not 2.
Then what about the chart where a = 0 and b = 0, the final answer given is also not operational so how come the final answer comes out to be the same as when the sign would be operational.
Tricky and just a few doubts. Help needed...
x*y = 1
there is just one possibilty according to the chart when x*y can equal 1, and that is if x=1 and y=1
(x*y)+x
(1*1)+1
acc ording to the chart,
1*1 = 1
1+1 = 1
Hence, (x*y)+x = 1
Option D