Maths

11 Plus Maths – Preparation and Information

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Rash
Posts: 134
Joined: Sun Sep 30, 2007 12:24 am

Maths

Post 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
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Re: Maths

Post 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?
Rash
Posts: 134
Joined: Sun Sep 30, 2007 12:24 am

Re: Maths

Post by Rash »

So do you divide 10 by8? Would this be a caculator or non calculator question? Ta
Enjoyingthejourney
Posts: 122
Joined: Mon Jan 04, 2016 12:44 am

Re: Maths

Post 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?
Enjoyingthejourney
Posts: 122
Joined: Mon Jan 04, 2016 12:44 am

Re: Maths

Post by Enjoyingthejourney »

He runs in 1.25 hours (75 minutes)
Rash
Posts: 134
Joined: Sun Sep 30, 2007 12:24 am

Re: Maths

Post by Rash »

Yes, she does. Thank you.
Albatross
Posts: 76
Joined: Wed Jan 29, 2014 10:42 pm

Re: Maths

Post 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!
Rash
Posts: 134
Joined: Sun Sep 30, 2007 12:24 am

Re: Maths

Post 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
Bee
Posts: 147
Joined: Wed Jul 13, 2016 9:36 pm

Re: Maths

Post 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.
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