Go to navigation
It is currently Fri Dec 09, 2016 11:13 pm

All times are UTC




Post new topic Reply to topic  [ 8 posts ] 
Author Message
 Post subject: math problem
PostPosted: Fri Nov 16, 2007 9:45 pm 
If it takes 8 minutes to drill 6 holes, how many holes can be drilled in 15 minutes

Could someone explain how work out the above question?

thanks for any help :lol:


Top
  
 
 Post subject:
PostPosted: Sat Nov 17, 2007 6:23 pm 
Offline

Joined: Thu Nov 08, 2007 9:57 pm
Posts: 1167
.


Last edited by Belinda on Wed Oct 31, 2012 9:53 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Sat Nov 17, 2007 10:34 pm 
Offline

Joined: Fri Sep 07, 2007 1:12 pm
Posts: 151
Firstly, I'm no expert but I would explain it the way my brain worked it out.

An obvious number fact is that 16 is double 8. Therefore, we know that 12 holes could be drilled in 16 mins as we have only been given 15 mins we would take the last drilled hole away! The answer therefore has to be 11.

I am assuming the answer has to be in whole holes!!


Top
 Profile  
 
 Post subject:
PostPosted: Sun Nov 18, 2007 9:49 am 
Offline

Joined: Mon Feb 12, 2007 1:21 pm
Posts: 11954
Belinda,

Your method is called the 'unitary' method as you are finding out how much '1' is by dividing then multiplying to get what you need. It works well for most children!

I like the 'approx' method above to - in a MC situation it would probably be good enough.


Top
 Profile  
 
 Post subject: Holes
PostPosted: Tue Nov 20, 2007 9:00 am 
stly, I'm no expert but I would explain it the way my brain worked it out.

An obvious number fact is that 16 is double 8. Therefore, we know that 12 holes could be drilled in 16 mins as we have only been given 15 mins we would take the last drilled hole away! The answer therefore has to be 11.

I am assuming the answer has to be in whole holes!!

I would say 12 holes rather than 11 - you have started on the 12th so you do have a hole, even if it's smaller than you are aiming for!


Top
  
 
 Post subject:
PostPosted: Tue Nov 20, 2007 8:05 pm 
I agree. Maths says you have 11.25 holes but common sense says you have 12 holes, the 12th one being less deep.

Is this an ill-thought-out question or a trick one?


Top
  
 
 Post subject:
PostPosted: Tue Nov 20, 2007 10:01 pm 
Offline

Joined: Tue Dec 13, 2005 12:49 pm
Posts: 1647
Location: berkshire
Aha....would .25 be a full hole or just a dent???? :D


Top
 Profile  
 
 Post subject:
PostPosted: Tue Nov 20, 2007 10:50 pm 
I think it's a badly thought out question - you could make a case for 11 or 12 and the last thing you want to do under pressure is worry about which one the examiner had in mind.


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
CALL 020 8204 5060
   
Privacy Policy | Refund Policy | Disclaimer | Copyright © 2004 – 2016