
PreCalculus PreCalculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
February 17th, 2018, 06:01 PM  #1 
Senior Member Joined: Aug 2014 From: India Posts: 255 Thanks: 1  How to solve this problem regarding clock strikes?
Question: A clock strikes once at 1:00 Clock and twice at 2:00 clock, thrice at 3:00 clock, and so on, respectively. How many total strikes per day? Solution: 1 + 2 + 3 + 4.........+ 12 = 12(13)/2 = 78 × 2 = 156 (Answer) My doubt  how can a clock hits "once at 1:00 clock" if 1:00 clock happens twice per day, i.e. 1 am and 1 pm? Last edited by skipjack; February 17th, 2018 at 06:52 PM. 
February 17th, 2018, 06:12 PM  #2 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,814 Thanks: 1046 Math Focus: Elementary mathematics and beyond 
When the clock shows one it strikes once, be it am or pm.

February 18th, 2018, 01:11 AM  #3 
Senior Member Joined: Aug 2014 From: India Posts: 255 Thanks: 1  I think you misunderstood the question, In my question there is also a sentence which says " twice at 2:00 clock, thrice at 3:00 clock". if you say "When the clock shows one it strikes once, be it am or pm." then it is impossible to twice at 2:00 clock, thrice at 3:00 clock. Are you saying question is wrong? 
February 18th, 2018, 01:44 AM  #4 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,814 Thanks: 1046 Math Focus: Elementary mathematics and beyond  At one pm the clock strikes once. At one am the clock strikes once. A two pm the clock strikes twice. At two am the clock strikes twice. At three pm the clock strikes thrice. At three am the clock strikes thrice. And so on.

February 18th, 2018, 02:08 AM  #5 
Senior Member Joined: Aug 2014 From: India Posts: 255 Thanks: 1  
February 18th, 2018, 02:10 AM  #6 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,814 Thanks: 1046 Math Focus: Elementary mathematics and beyond 
The clock chimes twice! Google "definition of chime" if you don't know what that means.
Last edited by greg1313; February 18th, 2018 at 02:14 AM. 
February 18th, 2018, 02:29 AM  #7 
Senior Member Joined: Aug 2014 From: India Posts: 255 Thanks: 1 
Solution: 1 + 2 + 3 + 4.........+ 12 = 12(13)/2 = 78 × 2 = 156 (Answer) Why they multiple with 13 and divided with 2. Last edited by Ganesh Ujwal; February 18th, 2018 at 02:42 AM. 
February 18th, 2018, 02:56 AM  #8 
Global Moderator Joined: Dec 2006 Posts: 19,058 Thanks: 1618 
The average of the first and last term is (1 + 12)/2 = 13/2. The sum is 12 (the number of terms) multiplied by the above average. 
February 18th, 2018, 03:05 AM  #9 
Senior Member Joined: Aug 2014 From: India Posts: 255 Thanks: 1  
February 18th, 2018, 04:14 AM  #10 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 12,610 Thanks: 845  

Tags 
clock, problem, solve, strikes 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Clock Problem  Aman Verma  Elementary Math  7  July 17th, 2014 09:23 AM 
pi clock  leodlion  Number Theory  10  January 22nd, 2013 01:24 PM 
three strikes and you are out, quadratic equation?  ed_v  Algebra  7  September 5th, 2012 10:28 PM 
Clock Problem  Recipe  Algebra  5  March 26th, 2010 01:20 PM 
The Clock  symmetry  Algebra  8  February 2nd, 2007 03:58 PM 