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**Nikky****Guest**

Can someone help with this?

...

A person drives at a constant speed of 97km/h except for a break that he takes which is 26.4 minutes long. If the average speed of the trip is 64km/h...

How long did the whole trip take?

How far does the person go?

**ryos****Member**- Registered: 2005-08-04
- Posts: 394

speed = distance / time

Average speed also = distance / time

Assume two chunks of time: t1 spent driving at 97 km/hr and t2=26.4min spend driving at 0 km/hr

Convert break to hours: 26.4/60 = 0.44 hr

Average the speeds: (s1 + s2) / (t1 + 0.44)

(97 + 0) / (t1 + 0.44) = 64

t1 = 97/64 - 0.44 = 1.075625

Or, total time = 1.515625 hr and total distance = 64 km/hr * 1.075625 hr = 68.84 km.

But, I may have done it wrong. It's late and I haven't checked for mistakes...

*Last edited by ryos (2005-10-18 18:15:43)*

El que pega primero pega dos veces.

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**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,063

Checked, found right.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**DAN****Guest**

I love maths. It's so fun and exciting. Please tell me more. Oh maths!! (Jelly babies)

**justlookingforthemoment****Moderator**- Registered: 2005-05-26
- Posts: 2,161

Insomnia...? You have a jelly baby fan friend.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,656

You can combine maths and jelly babies. Count them.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**insomnia****Real Member**- Registered: 2005-03-23
- Posts: 944

Actually I edited his post as he was being abusive. *I hate maths* was what he said. So I changed it.

Friends are angels who lift our feet when our own wings have trouble remembering how to fly

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,656

Oh, and they would probably be the first to notice if they didn't get the right change.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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