The operators * and + operate only on the numbers 0 and 1 as defin

Question

https://gmatclub.com/forum/download/file.php?id=48964 The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defined in the table. What is the value of x * y ? (1) (x * y) + y = 1 (2) (x * y) + x = 1 2019-07-15_1110.png

Archit3110 · Answer

from given info #1
(x * y) + y = 1
possible when y =1 and x=0 
x*y = 0
#2
(x * y) + x = 1
x=1 and y=0
x*y = 0
IMO D

omkartadsare · Answer

@Bunuel- Request you to explain the OA of this.

Posted from my mobile device

Rose2012 · Answer

Shouldnt this be C? as when x is 1 and y is 1 Statement 1 and 2 are met and we can arrive at that only with C option.

omkartadsare · Answer

@Rose2012- I got C as well,but OA says B. Maybe OA is wrong. But Bunuel hardly gets it wrong :-\

Posted from my mobile device

Bunuel · Answer

In (1) (x * y) + y = 1 is also possible when x = 1 and y = 1. According to the table, x*y = 1 and 1 + 1 = 1.

Kinshook · Answer

(1) (x * y) + y = 1
If y=1 and x=0 or x=1
x*y = 1 if x =1
x*y=0 if x=0
NOT SUFFICIENT

(2) (x * y) + x = 1
If x=1 and y=0 or y=1
x*y=1 if y=1
x*y=0 if y=0
NOT SUFFICIENT

Combining (1) & (2)
(1) (x * y) + y = 1
If y=1 and x=0 or x=1
(2) (x * y) + x = 1
If x=1 and y=0 or y=1
x=1 and y=1
x*y=1
SUFFICIENT

IMO C

MidhilaMohan · Answer

I think the OA is wrong here

with statement 1 we get 2 conditions 
i) x=0 y=1 or
ii) x=1 y=1

hence Not Sufficient

with statement 2 we get
i) x=1 y=0 or
ii) x=1 y=1

Not sufficient
 
Combining both statements we get x=y=1
IMO C

but the OA shows B..which in my opinion is incorrect.

The operators * and + operate only on the numbers 0 and 1 as defin

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards