Page 1 of 1
Maths
Posted: Mon Sep 26, 2016 1:14 pm
by Rash
Can anyone help pls. I need a simplest way to work the question below in order to explain it to a 10 year old.
1: Ravi runs 10km at a speed of 8km per hour. How many minutes before Jessica does he complete the run? (Jess completes the run in 100 minutes)
The question is about speed, distance, time. Time=S/D
So do you divide 10 and 8 by 2 and get 4 over 5 or do you divide both numbers and get 1.25. So confusing:( finding it difficult to explain. TIA
Re: Maths
Posted: Mon Sep 26, 2016 1:17 pm
by Guest55
Rash wrote:Can anyone help pls. I need a simplest way to work the question below in order to explain it to a 10 year old.
1: Ravi runs 10km at a speed of 8km per hour. How many minutes before Jessica does he complete the run? (Jess completes the run in 100 minutes)
The question is about speed, distance, time. Time=S/D
So do you divide 10 and 8 by 2 and get 4 over 5 or do you divide both numbers and get 1.25. So confusing:( finding it difficult to explain. TIA
Speed = distance/time so time = distance/speed
Does that help?
Re: Maths
Posted: Mon Sep 26, 2016 1:24 pm
by Rash
So do you divide 10 by8? Would this be a caculator or non calculator question? Ta
Re: Maths
Posted: Mon Sep 26, 2016 1:32 pm
by Enjoyingthejourney
Hi Rash. I would have assumed that all Maths questions at 11plus would be non-calculator. Is your child able to divide into decimals?
Re: Maths
Posted: Mon Sep 26, 2016 1:35 pm
by Enjoyingthejourney
He runs in 1.25 hours (75 minutes)
Re: Maths
Posted: Mon Sep 26, 2016 1:46 pm
by Rash
Yes, she does. Thank you.
Re: Maths
Posted: Mon Sep 26, 2016 11:47 pm
by Albatross
Interesting. If I had to explain this to a 10 year old I'd put it like this:
The first 8km takes 1 hour. Then the remaining 2km takes 2/8 hr, i.e. 1/4 hr, namely 15 mins. Total 75 mins.
I wouldn't expect a 10 year old to know equations about speed and time!
Re: Maths
Posted: Tue Sep 27, 2016 8:45 am
by Rash
Thank you Albatross,
That's exactly what I was struggling with, whether to let her work it out her own way or to introduce the equation, which she may find hard to remember at this stage. However, I've come to the conclusion that if the answer is correct and it doesn't matter how they got to it then I would leave it for now.
Although, after dividing the two numbers she got 1.25 but I believe when under exam conditions a child can easily get confused with 1 hour 25 minutes. :0
Re: Maths
Posted: Thu Oct 06, 2016 11:46 am
by Bee
We calculate it as below
Time = Distance/speed
10 km / 8 = 5/4 hours
Which is 1 hour ¼ mins. (1/4 hour is 15 mins)
So it is 1 hour 15 mins which is equal to 75 mins
I think it helps to know the formula for Speed & time.
I like the simple way Albatross has explained.