The Old techInterview Forum - two wrongs make a right

two wrongs make a right

Just wondering if anyone ran across this brainteaser. I was given it in an interview and didn't know even where to begin. all i remember about it was - the way the guy wrote it out.

W R O N G
+ W R O N G
----------------
R I G H T

something about assing numbers to the letters.

mohit sadani
Sunday, November 30, 2003

If I'm not mistaken the original has one or several of the letters replaced with numbers, it has been a long time since I've seen this though.

At its simplest this is just a quick test of how quickly you can determine valid values. If W +W = R, W has some limits, further since R + R = I, which may or may not affect the W+W=R part of the equation you can quickly limit W to 1 or 2, and thust limit R to 2,3,4,5. Similar problems exist, usually something like APPLE+APPLE=ORANGE or some such. Its all about determining possible values.

However your problem as presented doesn't allow for a quick solution to be determined as too many possibilities exist. If there were any other constraints provided (even "Using only 1-9"), please post.

Lou
Monday, December 01, 2003

The numbers assigned to the follwing values (0-9) should give one of the possible answers.

W=2, R=5, O=4, N=3, G=8

R=5, I=0, G=8, H=7, T=6.

The problem can be split into

W R
+ W R
-----------
R I
----------

and

O N G
+ O N G
------------
G H T
------------

Thereafter, its a case of trail-and-error for letter O to make
sure that no two different letters are assigned the same value.

Enigma77
Wednesday, January 28, 2004

Make all the letters equal to zero. (Nobody said this was against the rules.)

Derek Hofmann
Thursday, January 29, 2004

think i have an answer. the point is that each distinct letter stands for a distinct digit. e.g., G and N can't be the same digit.

W=3, R=7, O=0, N=8, G=1, I=4, H=6, T=2 works:
37081 + 37081 = 74162.

pA
Monday, February 09, 2004

another one:
24765+24765=49530

shaoji
Tuesday, February 10, 2004

I think the following should be the all answers:
12734
24765
25438
25469
25867
25938
37081
37091
49235
w=1,2,3,4 and consider all cases. g!=3 maybe useful.

shaoji
Tuesday, February 10, 2004

Totally off-topic, but I just read this .sig on (where else?) /.

"My English teacher taught me that two positives do not make a negative. Two words for her: "Yeah, right"."

Adriano Varoli Piazza
Thursday, February 12, 2004

We were assigned this for our eighth grade middle school math class. My answer was 37091+37091=74182. We were given that O must = 0, allowing us to extrapolate that G would equal 1, and therefore T would equal 2. Simple trial and error led to the rest.

Samantha Gooch
Monday, February 23, 2004