My Math Forum  

Go Back   My Math Forum > High School Math Forum > Elementary Math

Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion


Reply
 
LinkBack Thread Tools Display Modes
May 1st, 2019, 11:26 PM   #1
Senior Member
 
Joined: Aug 2014
From: India

Posts: 458
Thanks: 1

How to solve this fast and slow clock problem?

At 3:00 pm, clock was showing regular time. There are two clocks, one gains 5 min per hour. Another one loses 5 mins per hour. After how many hours both clocks will show the same time again?
Ganesh Ujwal is offline  
 
May 2nd, 2019, 04:45 AM   #2
Global Moderator
 
Joined: Dec 2006

Posts: 20,926
Thanks: 2205

Do the two clocks show whether the time is am or pm?
skipjack is offline  
May 3rd, 2019, 03:10 AM   #3
Senior Member
 
Joined: Aug 2014
From: India

Posts: 458
Thanks: 1

Quote:
Originally Posted by skipjack View Post
Do the two clocks show whether the time is am or pm?
YES. But how to solve the problem?
Ganesh Ujwal is offline  
May 3rd, 2019, 05:45 AM   #4
Global Moderator
 
Joined: Dec 2006

Posts: 20,926
Thanks: 2205

If the clocks show the same time initially, they'll next do that when they're out of step with each other by 24 hours (because they don't show the date). They get out of step with each other by 10 minutes every hour, so this will take 144 hours (because 1440 minutes is 24 hours).
skipjack is offline  
May 8th, 2019, 08:10 AM   #5
Senior Member
 
Joined: Aug 2014
From: India

Posts: 458
Thanks: 1

Quote:
Originally Posted by skipjack View Post
If the clocks show the same time initially, they'll next do that when they're out of step with each other by 24 hours (because they don't show the date). They get out of step with each other by 10 minutes every hour, so this will take 144 hours (because 1440 minutes is 24 hours).
Answer is 72 hours, I don't know how to do it?
Ganesh Ujwal is offline  
May 8th, 2019, 06:06 PM   #6
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 14,597
Thanks: 1038

Denis is offline  
May 8th, 2019, 11:07 PM   #7
Senior Member
 
Joined: Aug 2014
From: India

Posts: 458
Thanks: 1

Each hour clock A runs 5 minutes fast, after 12 hours, clock A is indicating 1 hour later than it should be. Although it is 3, it shows 4.

Similarly, because each hour clock B runs 5 minutes slow, after 12 hours, clock B is indicating 1 hour earlier than it should be. Although it is 3, it shows 2.

At t = 0h: Clock A points to 3. Clock B points to 3.
At t = 12h: Clock A points to 4. Clock B points to 2.
At t = 24h: Clock A points to 5. Clock B points to 1.
At t = 36h: Clock A points to 6. Clock B points to 12.
At t = 48h: Clock A points to 7. Clock B points to 11.
At t = 60h: Clock A points to 8. Clock B points to 10.
At t = 72h: Clock A points to 9. Clock B points to 9.
Ganesh Ujwal is offline  
May 9th, 2019, 05:48 AM   #8
Global Moderator
 
Joined: Dec 2006

Posts: 20,926
Thanks: 2205

The times (after 72 hours) wouldn't match, as one would be 9 pm and the other 9 am.
skipjack is offline  
Reply

  My Math Forum > High School Math Forum > Elementary Math

Tags
clock, fast, problem, slow, solve



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
how to solve this confusing clock problem? Ganesh Ujwal Elementary Math 4 October 17th, 2018 11:23 PM
How to solve this problem regarding clock strikes? Ganesh Ujwal Pre-Calculus 9 February 18th, 2018 04:14 AM
Clock Problem Aman Verma Elementary Math 7 July 17th, 2014 09:23 AM
Clock Problem Recipe Algebra 5 March 26th, 2010 01:20 PM
help me solve some basic topology questions for fast CASH!!! theBigShot Topology 0 November 8th, 2009 04:32 PM





Copyright © 2019 My Math Forum. All rights reserved.