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Homework Statement
A car moving at constant speed of 40 km/h in a straight road which heads towards a wall makes a 900 (90 degree) turn by the side of the wall. A fly flying at constant speed 100km/h starts from wall till car and when it reaches the car turns back and flies towards wall at same speed (100 km/h). This procedure starts when the car is 20 km away from the wall. The fly continues its journey till the car takes the 90 - degree turn.
So how many trips has the fly made between the car and wall?
Homework Equations
[tex]
distance = speed * time
[/tex]
The Attempt at a Solution
[PLAIN]http://img294.imageshack.us/img294/2922/suma.png
A is the initial position of car. B is the position where the fly first meets the car. O is the wall.
So let x = 20km be distance from car to wall.
Let t be time taken for car to reach from A to B
Now
AB = 40t
OB = 100t
but,
x = AB + OB
t = x/140therefore
[tex]
OB = \frac{5x}{7}
[/tex]This is all that I got...
When I checked answers it says infinite...
I just don't get it..
Please Help!
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