## February 20, 2011

### 100 Meter race

Andy, Barry, and Carl race each other in a 100-meter dash.
They each run at a constant speed throughout the sprint.
Andy beats Barry by 20 meters, and Barry beats Carl by 20 meters.
How many meters does Andy beat Carl by?

Jürgen said...

Andy ran with 100% speed.
Barry ran with 80% speed.
Carl ran with 64% speed.

When Andy reached the 100m finish line, Carl was at 64m line.

100-64=36

Anonymous said...

36 meters

number seven said...

Andy beats Carl by 36 meters.

Anonymous said...

It’s funny how many articles and news come out on a weekly basis.

Tony said...

36 meters..

ie, 80 percentage of 80

Anonymous said...

andy beat carl by 40 meters. it could not be 36 meters, because no matter how fast they ran when barry crossed the finish he was 20 meters behind andy and 20 meters in front of carl. so andy beat carl by 40 meters

Anonymous said...

"o matter how fast they ran when barry crossed the finish he was 20 meters behind andy and 20 meters in front of carl"

This is incorrect, had the race continued beyond the 100m mark, once barry crossed that 100m threshold, andy would have been more than 20m in front of him.

andy's speed is (5/4)barry's speed and barry's speed is (5/4)carl's use these equalities and you should get you to 36.

Anonymous said...

40m

Andy was 20m in front of Barry

Barry was 20m in front of Carl

20+20 equals 40

It has nothing to do with what percent of speed they ran, the question gives you exact measurements to go by

Anonymous said...

Anonymous said...

for those of you who think the answer is 40, think sbout this. What would happen if the race was only a 20 meter race? If Andy and Barry were to run, would that mean Barry ran 0 meters? I think not.

I think that Barry runs 80% of Andy's distance and Carl runs 80% Barry's distance. Which means when Andy finishes, carl will be 36 meters behind.

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Anonymous said...

40 meters

they all running at constant spped

Andy 1(speed)*100 = 100 meters
b--- 0.8(speed)*100 = 80 meters
c--- 0.6(speed)*100 =60 meters

Anonymous said...

Andy is 20 meters ahead of of Barry when he crosses the line.
Barry is 20 meters ahead of Carl when he crosses the line.
each running at a constant speed the variance from Andy to Barry is 80%
variance from Barry to Carly is 80%
100 over 80 = 80 over X
100x=6400
x=64
therefor Carl was 64% finished the race while Andy was 100% finished.
Meaning that Andy beat Carl by 36 meters.

shivani singh said...

It seems easy puzzle, most of you think answer is 40. but not this is not the answer. you need to apply some basic formula like speed = distance over time
then time = distance over speed
For Andrew and Britney,
time = 100/speed of Andrew = 80/speed of Britney
then speed of Britney = (80/100)*speed of Andrew = 4/5*speed of Andrew

For Britney and Carl,
time = 100/ speed of Britney = 80/ speed of Carl ,
then speed of Carl = 4/5* speed of Britney = 4/5*4/5*speed of Andrew = 16/25*speed of Andrew

distance cover by Carl = speed of Carl * time = 16/25*speed of Andrew* 100/speed of Andrew = 64 meter
so, Andrew beats Carl by 36 meter.