Make some assumptions: 1. the circumference of a quarter is ___ inches. 2. the average ridge is 0.__ inches wide. 3. do the math.

Jon A. was on the right track. There are only 2 ridges which "go around" a quarter...the top ridge (heads side) and bottom ridge (tails)!

2 - one around the top and one around the bottom.

Just dip in ink and make it roll on a piece of paper, then count!

So what is the correct answer? I am persuaded by Dan B. and Jon A. that the answer to this question is "2" -- AND SHOULD ONE ASSUME, such a trick, or a tricky, question during a job interview, that the answer ought to be calculable right then and there? If so, common sense dictates that the answer in this case does NOT involve counting individual ridges positioned orthagonally to the face of the coin.... p.s. I have not searched elsewhere for an answer but rather am restricting my wondering to this site.

oops - this sentence should have started - "AND SHOULD ONE ASSUME, for such a trick, or tricky, question..."

looks like Steve got the job cuz he looked it up!

Phil had a very clever answer that interviewers would love.

Twice as many there are along 1/2 the coin's circumference.

I don't know...let's count them.

None of the ridges on a quarter go around it. All of the ridges on a quarter are orthogonal to the plane of the faces.

Who cares.

Enough to go all the way around!

4. If you go around the face of the quarter, you'll pass 4 ridges.

Count the troughs. There will be an equal number of ridges.

Work for someone else??