







When are the hands of a clock perpendicular? 
20180111 

From Nazrul: How many times in a day are the hands of a clock perpendicular to each other? How can I find the times? Please help me. Answered by Penny Nom. 





A clock takes 3 seconds to strick the hour of 3 o'clock 
20120309 

From saptarshi: [ A clock takes 3 seconds to strick the hour of 3 o'clock. How many seconds will it take to strick 9 o'clock?] Answered by Robert Dawson. 





The equation of a circle 
20101020 

From Silvan: Hi, I just want to find the x,y values for the circumference of a circle...
Lets take a clock having its centre at (0,0) in a graph.
I just want to know how to find the (x,y) coordinates for the curved path or the surface of the circle..
Is there any formula to directly align the curved path or the circumference of the circle in a graph for a known radius of a circle..
I feel it will be useful for me to draw a clock in a graph... :) Answered by Penny Nom. 





The distance travelled by a minute hand 
20100306 

From Patric: How much distance will the minutes hand of length 14mm of a clock
cover in moving from 5 to 10? Answered by Penny Nom. 





Percentage of an hour 
20081015 

From JESSICA: HI I AM IN GRADE 7 AND FOR MATH HOMEWORK MY TEACHER ASKED US
TO MAKE 8 DIFFERENT TIMES(clocks) AND TELL HIM WHAT THE PERCENTAGE
FOR THE TIME IS.
BUT I DON'T KNOW HOW TO CONVERT TIME TO A PERCENT.
PLEASE HELP ME??!!??
JESSICA
SEVENTH GRADE Answered by Penny Nom. 





The angle between the hands on a clock 
20080404 

From Kristin: The question I need help with is : Bobo looked at the clock at 1:25. What was the precise measure of the angle formed by the hour and minute hands of the clock? Assume that each of the clock hands moves at a constant rate continuously around the face of the clock. Thus, in any given fractional part of an hour, each hand will move that same fractional part of an hour's worth of movement. Answered by Stephen La Rocque. 





A 24 hour clock 
20080131 

From CARLA: at a certain time i looked at a 24hour digital clock and noticed some things about the time. (1 The number in the hours section plus the number in the minutes section makes 60.(2 One of the digits in the minutes section is the square root of the other digit in the minutes section.(3 The sum of the digits in the minutes section is the number in the hours section reversed. what is the time? Answered by Penny Nom. 





Partitioning a clock face 
20071219 

From Kim: Using a clock with a regular circular faced dial, draw two straight lines such that the sum
of the numbers in each of the three areas is equal. Answered by The team at Math Central. 





Rate of change of distance between the clock hands 
20070605 

From Jonathan: A certain Clock has a minute hand with a length of 4 inches long and an hour hand with a length of 3 inches long. How fast is the distance between tips of these hands changing at 9:00? Answered by Stephen La Rocque. 





Angle of clock hands 
20070131 

From Sophia: How many degrees are in the aute angle formed by the hands of a clock at 2:20 p.m.? Answered by Stephen La Rocque. 





A clock chimes 7 times in 7seconds 
20040502 

From Anna: A clock chimes 7 times in 7seconds. how long does it take the clock to chime 10 times? Answered by Penny Nom. 





10 hours before 7:15 
20021027 

From Jessica: It is evening 7:15. What time would it be 10 hours earlier? Answered by Penny Nom. 





Counterclockwise 
20010914 

From Rolanda: When Descartes invented the coordinate system he decided to number them counterclockwise. Why? Answered by Chris Fisher. 





When did the man go out? 
20001214 

From Rajesh: A man goes out in time between 5 and 6 and when he comes back he observes that two hands have interchanged position. Find when the man did go out? Answered by Penny Nom. 





Three problems 
20001214 

From Sarah: Hi, my name is Sarah, and I'm asking this question on behalf of niece who is in secondary two. Thank you. Q1. What is the angle formed by the hour hand and the minute hand of a 12 hour clock at 5.50pm. . . . Answered by Penny Nom. 





Why counterclockwise? 
20000221 

From Drew: Why do the numbers of quadrants in a graph increase in a counter clockwise pattern? Why aren't they numbered increasingly in a clockwise pattern? Answered by Chris Fisher. 





A goofy clock 
19991120 

From Kate: While repairing a watch, a jeweler removed the hands and inadvertently replaced the hour hand on the min. spindle and vice versa. he set the hands to read 2:00pm, which was the correct local time when I picked up the watch. A few minutes later, I noticed that the hands were taking goofy positions. What was the first time thereafter that the watch would show the correct local time? Answered by Chris Fisher. 





Clockwise or Counterclockwise? 
19991027 

From Tim: A particle moves around the circle x^{2} + y^{2} = 1 with an xvelocity component dx/dt = y  Find dy/dt
 Does the particle travel clockwise or counterclockwise around the circle? Why?
Answered by Harley Weston. 





Modular Arithmetic 
19990204 

From Leslie Kupper: I am trying to do a project on modular arithmetic. I was wondering if there were any websites that include a sample lesson plan on modular arithmetic for any grade level. Let me know where and how to find them. Thanks. Answered by Harley Weston. 





Hour Hand Movement 
19980419 

From Chris and Angela Bradley: My wife and I are haveing an argument over the answer to this question, what is the total number of degrees through which the hour hand of the clock moves in 3 hours and 18 minutes? Thanks in advance. Answered by Chris Fisher. 





Clock Arithmetic. 
19980309 

From Joann Dixon: What is clock mathematics? Answered by Patrick Maidorn. 

