## Interview Question

Software Developer Interview

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# Calculate the angle of two clock pointers when time is 11:50.

34

30+25=55 angle between them...

Anonymous on

25

You know that there is 30 degrees between each number on the clock because 360/12 = 30. You know that the minute hand is at exactly 10, while you know that the hour hand is 5/6th of the way to the 12 (from the 11) because 50/60 = 5/6. Therefore to get the total angle, you must add the 30 degrees from the 10 to 11 plus the 5/6 distance from 11 to 12, and you get 30 degrees + (5/6 * 30) = 30 + 25 = 55 degrees. So the final answer is 55 degrees.

Isaac on

21

Anonymous is on the right track with the hour hand going 0.5 degree/minute, but at 11:50 the hour hand is no longer near the 11, it's near the 12. 10 minutes before 12, it is 5 degrees from the 12. The minute hand is 60 degrees from the 12 in the same direction (360 deg=60 minutes, so 60 deg=10 minutes). Angle between the hands is the difference between these two: 60-5 = 55.

Anonymous on

12

360 degrees in clock. clock has 12 positions, The hour hand is 5/6 way to position 12 (Hour hand travels between the hours!!!!) and the minute hand is exactly on position 10. so If between every position is 360/12 or 30 degrees. then the minute hand is 60 degrees from 12 and the hour hand is 1/6 of 30 from 12... or 5 degrees Answer is 60-5= 55

SE on

9

Here's a simple way to look at it. If the hour hand was exactly on 12 then the angle would be 60 degrees. However since the hour hand is just short (by 10 minutes) of the twelve, you need to subtract 10 minutes x .5 degrees per minute giving you 60 - (.5 x 10) or 60 - 5 = 55 degrees.

Chuck on

11

The answer is really 55 degrees.

Miolya on

5

55 or 305.

ed on

3

the best answer is the ask the client if they are looking for the acute or reflex angle. This is a test to clarify with clients and not to assume anything. See the whole problem not just the simple answer. Then you can get into your math.

bk on

3

oops, points off for being a smart ass: I meant "reflex" angle. (more than 180 degrees) - "obtuse is more than 90...but they'd get the message: that the interviewee can see things in more than one way...

Bill on

2

easy. 55 degrees.

mike. on

2

The hour pointer moves 360º in 12 hours, that's 0,5 degrees per minute. The minute pointer moves 360º in 60 minutes, that's 0,1 degrees per second. At 11:50, the hour pointer moved 710 minutes (11*60) + 50, so it's at 355º At 11:50 the minute pointer moved 3000 seconds (50*60), so it's at 300º The correct answer is 355-300 = 55º

Ecardenal on

3

Maybe if they asked their prospects "what is your understanding of due diligence" instead of asinine clock questions, they would be in far better shape today.

gatecrasher on

2

The answer is 55 degrees. There are 30 degrees between each number on a clock. (360 / 12 = 30). The answer isn't 30 degrees, because at 11:50, the hour hand will not be exactly on the 11 anymore. The only time the hour hand is exactly on the 11 is at 11:00. At 11:50, the minute hand is on the 10 and the hour hand is 5/6 of the way between the 11 and 12. At 11:50, the minute hand is exactly on the 10 and the hour hand is 5/6 of the way between the 11 and 12. 5/6 of 30 degrees is 25. So between numbers 10 and 11 is 30 degrees. Then add another 5/6 of 30 degrees for the distance between the 11 and where the hour hand is now. So 30 + 25 = 55 degrees.

Chris J. on

2

There are two angles formed. The interviewee should reply by asking the interviewer if he/she wants him/her to calculate the acute one or the obtuse one.

Bill on

1

And then, Alex is right, is 55 degrees

Edmundo Gerardo on

1

55 if the clock is Swiss.

ektormelendez on

3

Using only a compass and a protractor, trisect an angle using a gemoetrically correct proof.

robert on

8

Is it an analog or digital clock? And are they both on the same clock?

Jimmy on

1

I know of the arms of a clock, but have never heard of clock pointers. I imagine a clock pointer is someone pointing at a clock when the time is 11:50. The angle between them would be relative to a reference point and distance. What are those parameters?

Jim B. on

1

1. minute hand: 360 degrees, 60 minutes in one hour -> 6 degrees per minute for the minute hand 2. hour hand:1h for the hour hand is the same as 5 minutes for the minute hand -> one hour for the hour hand equals 30 degrees 3. 30 degrees for 60 minutes for the hour hand -> 0.5 degrees per minute for the hour hand 3. position of minute hand at 50min: 6*50=300 degrees 4. position of hour hand at 50min:330 (11hours)+50*0.5 (50 minutes)=355 5. angle between them is 55 degrees

Fabian on

1

"What a messed up angle of those clock hands: I'm either really early for lunch, or need to be getting paid overtime to be here this late."

Alex Marshall on

1

http://en.wikipedia.org/wiki/Clock_angle_problem

wikipedia on

1

where in the room are these clock pointers positioned? (and do they actually just stay there and point at the clock all day?)

Jim on

0

Where are the two clock pointers standing in relation to the position of the clock depicting 11:50? Also, don't they know it's rude to point.

KS in NYC on

0

Input: hours: 11 and minutes: 55 formula: abs (( 30 * hours ) - ( 5.5 * minutes)) output = abs ((30 * 11) - ( 5.5 * 55)) = ( 330 -302.5) = 27.5 Answer is 27.5 degree

Rathinavel on

0

Calculate the angle of two clock pointers when time is 11:50. ok let’s look at the question it asks for the angle of both pointers it’s not asking what the angle is from or to each pointer so you need to have at least 2 answers one for pointer a and one for pointer b but as its given no start point to calculate from my answer would be to ask for the missing information the angle of pointer a from what and the angle of pointer b from answer

matt on

0

I'm surprised nobody did this in radians. The distance between the 11 and 12 is 2Pi/12. As the minute hand moved to 11:50, the hour hand moved 10/12 of 2Pi/12. 2Pi/12 + 10/12*2Pi/12 = 2Pi/12 + 20Pi/144 = 24Pi/144 + 20Pi/144 = 11Pi/36

Sean on

0

25 degrees

0

55 degrees

0

The Answer is 25 degrees. The degree between 11 Hour Point and 12 Hour point is 30 degree (360/12). Since the time is 11:50, the minute pointer has completed 5/6 of a full round (360). So the hour pointer would also have moved 5/6 of the distance bwtween 11 and 12 hours. Therefore 5/6 of 30 Degrees is 25 degrees.

Lobsang on

0

Sorry, in my earlier calculation I missed out something. The Answer should be 30+25 = 55 degrees.

Lobsang on

0

acute or reflex

neha jagare on

0

depends upon the number of pointers your clock have....3 or 2 pointers

Chirag Sarang on

0

hosein on

0

54= 30+24

hosein on

0

Angle between each digits on a analog clock is 360/12 = 30degress. At 11:50, Minute hand will be on digit 10, and Hour hand will somewhere between digit 11 and 12 Lets split the total angle into 2 parts - a)Angle between digit 10 and 11 b) Angle between digit 11 and hour hand. a) Angle will be 30 degrees as angle between any 2 digits is 30degrees b) For covering each minute hour hand moves by 1/60 X 30 degrees , ie .5degrees So for 50 minutes, it covers .5X50 = 25 degrees. thats gives the angle between digit 11 and hour hand when the time is 11:50. So total angle is 30+25 = 55 degrees

Joseph on

0

50

Raja sekhar on

0

ohhh 55

Raja sekhar on

0

60 DEGREE...

JOHN on

0

55 or 305 degrees. The main learning from this pool of answers is: ' there are always a huge huge number of fools'. Being a 5th std Qn this cud be answered without a single wrong answer.

Binit on

0

the angle of the 9 and the 12 of a clock is 90. 9 to 10 to 11 to 12 make up 3 equal segments 90/3=30 move one segment 90-30=60 BOOYAA!!!!!

knoitall on

0

There are 90 degrees between 9 and 12, the minute hand is on the 10 and the hour hand is 50/60 or 5/6 from the 11 to the 12. Between 10 and 11 there are (90 * 1/3) = 30 degrees. To this you have to add 5/6 of the degrees between 11 and 12 or (90 * 1/3 * 5/6) = 25. Therefore the answer is 30 + 25 = 55 degrees.

Alex on

0

That is the reason you gringos need ilegals even for think for you. None of your answers are right, close but not right To begin the hour pointer already moved 5/6 to the 12 o clock position or in the 11 hrs, 58 minutes and 20 seconds (8.33), the minute pointer is in the 50 minutes position, is 30 degrees for 10 minutes separation , so the answer is 30 * 5/6 = 25 degrees, need confirmation, use a transporter thanks to the USA education system saludos

Edmundo Gerardo on

0

The interviewer wants to know if the canidate has a strong analytical and scientific background. There are many ways to answer the question correctly. However the best way is to give an answer to both the acute angle and the obtuse angle of the clock pointers. In this case it is 360 and 3240 arc seconds respectively. If the interviewer does not understand the answer you can convert the answer to different units and demonstrate you have what it takes to explain scientific concepts and ideas and are aware there is more than one solution to a problem. The question made me smile as its a freshmen engineering question at my alma mater. Graduates of my school are expected to answer these questions on there feet during a job interview and these types of questions are practiced.

EB on

0

I can only calculate time not it's angles

Anand Arun on

0

30

Miska on

0

@gatecrasher: LMAO! How perfectly acerbic...can I come work for you?

JAF on

0

30 degrees

kebede Midekssa on

1

But how do we know it is an acute angle vs. obstuse?

Anon on

1

Anon..it doesn't matter. It can't be done.

robert on

2

I think most people are seriously complicating the question. 360/12 = 30. http://www.mathsisfun.com/activity/clocks-angles.html

Marg on

1

Imagine that this clock was drawn on a piece of paper. Take any of the one of two hands on the clock and draw a line from it so that the line is perpendicular to the other. This will create a right triangle. Take the inverse tangent of the height of the triangle (the line that you drew) over its length (the hand that is not the hypotenuse of the triangle) and this will give you a precise angle between the hands of the clock.

Justin on

1

what's wrong with you? The answer is 30 or 25 degrees, depending if your clock point directly at 11 or is at 5/6 of the 11 position as is still 10 minutes to eleven o clock... why? The difference between the 10 (that is 50min) and the 11 is 30 degrees, that is 360 /12. If the hour tick is not still at eleven then you need to SUBSTRACT the difference, that is 5/6 of 30 degrees that is 5 degrees... result 25 degrees...

javier on

0

Has to be 5 degrees. It cant be 55 degrees because if u think abt it, thats the angle made if one hand is on the 12 and the other between 10 and 11.

DCraz on

0

30

4

5 degrees. At 11:50 the second hand is at 12, 0 degrees, and the hour hand is 5 degrees from 12, hence there are 5 degrees between them. The question did not specify _which_ hands.

Bill on

0

The hour hand would be pointing at 335 degrees and the minute hand 300 degrees; so 35 degrees.

robert on

2

it is same as 01-10

Kaushal Chawda on

6

360/12=30

xy on

2

Definitely 30 degrees. A circle is 360 degrees and there are 60 minutes on a clock which is a perfect circle. The angle between the two hands in this case is obviously 5 minutes. So (360 deg./60 min.) * 5 min. = 30 degrees.

Joe on

7

27.5 degree.... hour hand is 0.5 deg per min and minute hand is 5deg per minute.... so minute hand is 30 deg away from 11. while hour is 2.5 degrees away fro 11. 30-2.5 = angle between them...

Anonymous on