In an consultation setting , even the most canonic questions can palpate boldness - racking . If you ’ve ever draw and quarter a blank when asked to babble about your hobbyhorse , just imagine having to calculate the number of piano tuners in all of Chicago under that same sort of pressure .
Some private-enterprise technical school company are ill-famed for asking heavy - to - answer questions like this one . The interviewers who use them are n’t always looking for concrete figures , but rather they ’re essay to approximate the candidates ’ creativity and problem - solving skills . And while you may not know the exact numeral of piano tuners in Chicago off the top of your head , there is a “ correct ” line of thought you may watch to find oneself out .
These baffling brainteasers are becoming less common in the consultation process ( Google , one of the worst offenders , banish them a few age ago ) , but if you ever notice yourself face with one , here ’s how to answer like you know what you ’re talking about .
1. HOW MANY GOLF BALLS CAN FIT INSIDE A SCHOOL BUS?
Here ’s an example of a motion where the interviewer is n’t expecting you to blurt out a specific figure with no context . There are flock of variable at play here , and the more questions you ask the better flick you ’ll paint of your problem - work out operation . “Is this a received schooling bus ? ” “ How large are the golf game testis ? ” “ Is this accounting for the seats inside ? ”
Once you figure out the dimension of the schoolhouse busbar , you could calculate its volume into cubic inches then divide that number by the volume of a golf ball ( 2.5 three-dimensional inch ) . The result would be the number of golf game glob you could correspond into the quad when it ’s completely empty ( ignoring any gap between the golf game balls ) . To account for arse and other equipment , you have to estimate what percentage of the space is really empty and procreate that by your original golf game Lucille Ball figure .
If astandard schooling busis 8 metrical unit wide,6 feet gamy , and 20 feet long , and75 percentof the interior is unoccupied , then it could theoretically fit 495,000 golf ball ( though if you ’re taking into account the crack between the golf game ball , it would be closer to 350,000 ) . If you care more about being right than actually getting the chore , finger free to shout out this number with no account .
2. WHY ARE MANHOLE COVERS ROUND?
This may seem like an open - ended inquiry designed to assess the answerer ’s personality , but the reasoning behind the manhole covering fire ’s design is amazingly straightforward . As we’veexplained here before , round covering fire are unequal to of falling through manhole no matter how you put them . The ‘ backtalk ’ lining the rim of the opening ensure that the cover is always panoptic than the hole . cover that are straight , rectangular or oval in shape hazard come down through if they ’re inserted diagonally . Answering the question with these facts to back you up testify that you ’re a logical thinker — or that you ’ve spent too much time pondering your city ’s infrastructure .
3. HOW MUCH SHOULD YOU CHARGE TO WASH ALL THE WINDOWS IN SEATTLE?
Like the golf glob question , this problem can only be resolve by making an educate guess at several variables . If Seattle consist of 10,000 city block with 600 window per block , and the window washer spends five minutes per window while being paid a rate of $ 20 per hour , the answer would be approximately$10 million . On the other mitt , the power to keep thing simple can sometimes be just as worthful as on - the - tent flap mathematics skills . In that case , an reply like " $ 10 per windowpane " ( and you ’d get paid 6 time as much ! ) would also suffice .
4. HOW MANY PIANO TUNERS ARE THERE IN THE CITY OF CHICAGO?
If you were expect this question in a business audience , your natural response may be to laugh , cry , or perhaps flee the building as fast as possible . But with the help of some neat math deception , you’re able to actually come up with a pretty tightlipped approximation of the number using what little datum ’s available .
This eccentric of interrogative sentence is bang as aFermi Problem , and it can be puzzle out by slightly overestimating and underestimate the pattern using ability of ten with the presumptuousness that they ’ll balance each other out in the close . To start you necessitate to figure out the number of multitude living in Chicago . rather of amount up with an exact number you could apply 10 to the sixth , which equates to 1 million , to defend the universe ( the actual population of Chicago is just under 3 million , but we ’re estimate ! ) . Next , you require to forecast what share of the universe owns a forte-piano . If it ’s one out of every 100 masses , that ’s represented by 10 to the great power of negative two , which when multiplied by ten to the sixth equal ten to the fourth ( this may be starting to look complicated , but using the king of ten is in reality how mathematicians are able to keep big numbers manageable ) .
Ten to the quaternary is the same as saying 10,000 pianos . To figure out the number of pianoforte radio set ground on that figure , you may take on that piano tuners are capable to tune ten squared pianos each year . By dividing the number of piano by the numbers of piano tuned each year , you come up with the result that there are ten squared , or 100 piano tuners in Chicago .
Thanks to all the overvaluation and underestimations cancelling each other out , you’re able to count on ending up with a issue that come down within one fiat of magnitude of the correct result . Of course if you already have a Chicago phone ledger on manus , you could just count the act of piano wireless manually and notice that there are actually around 81 — but then you ’d be miss out on all that fun maths .
See Also:8 Illegal Interview motion
5. HOW MANY TIMES DO A CLOCK’S HANDS OVERLAP IN A DAY?
Without give the doubt much cerebration , you might mechanically assume the answer to be 24 , one overlap for each hour of the day . But , this being a list of sly job interview questions , you’re able to probably suppose that this answer is wrong .
The only clip the moment and the minute hand come together dead on the hour is at 12 type O ’ clock . After that the overlap occurs slightly after 1:05 , then slenderly after 2:10 , etc . By the time the minute hand get up to the 60 minutes hand the eleventh clip , the hr hand has had enough of a head start out that they do n’t bilk paths until 12 oxygen ’ clock , thus beginning the second twelve - minute cycle of the day . This stand for that there are only 11 meter the two hands overlap every 12 time of day , so they come together a total of22 timesduring one day .
Now try explain all that coherently to a prospective employer while asseverate eye tangency and an upbeat attitude .
6. AN APPLE COSTS 40 CENTS, AN ORANGE COSTS 60 CENTS AND A GRAPEFRUIT COSTS 80 CENTS. HOW MUCH IS A PEAR?
There are several style to tacklethis question . One path is to look at the letters in the word of honor themselves . If each vowel sound is worth 20 cents , then you may resolve that a Pyrus communis wouldcost 40 . If you were being show this interrogation out loud as opposed to read it , you might opt to interpret “ pear ” as “ pair . ” In that cause aclever answerwould be 80 cents for two apples , $ 1.20 for two orange and $ 1.60 for two grapefruit .
7. HOW MANY TRAFFIC LIGHTS ARE IN MANHATTAN?
Initially this question vocalize similar to the pianissimo tuner problem in that it can only be solved using the power of ten . While that ’s probably the case of thinking interviewers are looking for , you could always take the gentle path and pull up New York City ’s Department of Transportation webpage ( as of June 30 , 2011 , there were2820 traffic signalsin Manhattan ) .
8. HOW MANY BASKETBALLS CAN FIT IN THIS ROOM?
This is similar to the golf balls in a schooling bus problem , but this time the interviewee has the added advantage of being able to visually judge the dimensions of the space that ’s being filled . you’re able to go about solving it using the same straightforward maths equivalence , or you’re able to show off your originative thinking skills by asking some out - of - the - corner questions first . A question like"Are the balls amplify or can I deflate them first?”demonstrates that you approach problem in a thoughtful way and are able to come up withsmart solutionsto achieve the best final result .
9. WHAT DO WOOD AND ALCOHOL HAVE IN COMMON?
The direction you suffice this question present potential employers how you ’d go about finding common ground between two seemingly unrelated construct . For this special example , acceptable solution could admit thatboth textile are inflammable , or that methanol , a eccentric of alcoholic drink , is traditionally made from wood .
10. HOW DO YOU MEASURE THE WEIGHT OF A BABY ELEPHANT WITHOUT A SCALE?
Being stuck with a baby elephant and no scale to weigh it with is quite a predicament , but the problem can be resolve using aresourceful trickyou may have discover about in high school . you may fulfill a large cylindric methamphetamine vat with water not quite to the top , place a gravy holder in the water and strike off the water layer . Then you put the elephant in the boat ( which is likely harder than just buying a scale ) and mark the new water level . mensurate the difference between the two marks and with a little math you could easy calculate the exercising weight of the elephant . Let ’s hope that literally have to do this is n’t part of the job verbal description .
