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5 replies to this topic

### #1 chanakyavg

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Posted 23 March 2008 - 06:09 AM

A car is traveling at a uniform speed. The driver sees a milestone showing a 2 digit number.

After traveling for an hour the driver sees another milestone with the same digits in reverse order.

An hour later he sees another milestone containing the same two digits with a zero in between .

What is the average speed of the driver?
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### #2 bonanova

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Posted 23 March 2008 - 06:21 AM

A car is traveling at a uniform speed. The driver sees a milestone showing a 2 digit number.
After traveling for an hour the driver sees another milestone with the same digits in reverse order.
An hour later he sees another milestone containing the same two digits with a zero in between .
What is the average speed of the driver?

Spoiler for A leisurely
Nice one ... !
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### #3 chanakyavg

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Posted 23 March 2008 - 06:24 AM

Spoiler for A leisurely
Nice one ... !

Thanks hope u enjoyed it. :-D
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### #4 storm

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Posted 23 March 2008 - 07:03 AM

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### #5 woon

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Posted 23 March 2008 - 06:49 PM

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### #6 chanakyavg

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Posted 23 March 2008 - 08:07 PM

This is how i got to the answer:

Let the number on the 1 st mile stone = 10x + y
After an hour number on 2 nd mile stone = 10y + x
An hour later number on the 3 rd mile stone = 100 x + y

Since he crosses the mile stone after every hour with a uniform speed,

Distance covered in I st hour = Distance covered in the 2 nd hour

(10 y + x ) - (10x + y) = ( 100x + y ) - ( 10 x + y),

by solving we get, y = 6x or x/y = 1/6

When x = 1 , y = 6

So it is 16, 61 and 106, thus he was traveling at 45 mph or 45 Kmh
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