Monday, May 12, 2014

Hammer and Nail Interview

Check this out. A tough interview question here: http://www.businessinsider.com/ceo-asks-candidates-this-trick-math-question-2014-5

"A hammer and a nail cost $1.10, and the hammer costs one dollar more than the nail. How much does the nail cost?"

If your answer is $0.10 for the nail. Sorry, you are wrong. Probably no job offer. Bye.

Now this question may not be realistic, because for around a dollar you can only buy a toy hammer.

This is a tricky question because you may mentally split up $1.10 into $1 and 10 cents. If you say the nail cost a dime, oops 0.1 + 1.1 is 1.2 not 1.1.

I think the candidates may do better if the cost is some odder value such as $2.30. But then the nail will become too expensive.

Now, I admit. My first instinct was $0.10 too then soon I realize it isn't correct. And I know how to find the answer for sure, but so should all high school freshmen.

Look, first step is to assign variables. h=hammer, n=nail. Write down the information you know.
"A hammer and a nail cost $1.10". So h + n = 1.1, and.
"hammer costs one dollar more than the nail" , h = 1 + n.

Look, you got 2 equations and 2 unknowns, you got a system of equations. And this one is easy. Just substitute that 1+n in second equation into first equation. So 1+n+n=1.1, boom knock 1 out of both sides. 2n = 0.1, so n = 0.05. The nail costed a nickel.

Now the good math student would verify this answer. So the hammer costs $1.00 more so it is $1.05. Add them up you have $1.10. (How do I insert a little square icon?)

Did somebody say Algebra I is useless? It can be job offer vs no job offer.

And if the job interview ask me something like you got a river and you need to move missionaries and cannibals. I WALK OUT. I don't need this job.

2 comments:

Bertha Chan said...

So are you saying that he should get 1 hammer and 2 nails out of 1.1?
But it obviously said 1 hammer and a nail. So what goes wrong? This is why I never believe in (know) math. :D

Unknown said...

Thanks for explaining that in a way I can understand. I'm not really math inclined. However, I don't think that job interviews, plural or otherwise, can ask questions. I'll stick to grammar, thanks.