Its pretty sure that, If the camel takes all the 1000 bananas at once to the end point,he would be left with 0 bananas at the end.
So, there needs to some Intermediate Points that are in between O km and 1000 km.
So, to prove my point, Let us assume 4 points.
let's called point A------>Beginning Point
point B------> End Point
point Q------>First Intermediate Point
point W------>Second Intermediate Point
3000 2000 1001 533
<------5X----------> <----3Y-----> <------------Z--------------------->
A--------------------Q-------------W------------------------------------B
If we take 1000 bananas at once to 1km,then there will be 3 trips forward, and 2 trips backward, so , there will be a total of 5 trips.
A<----------5x---->Q
so, When we take 1000 bananas, we are only left with 600 bananas and similarly for the other one, but for the last one, there will be only 1 forward trip and so, its a total of 5 trips.
Let's prove that with a simple equation,
3000-5X=2000
X=200
So, Point Q is 200km away from the begining.
Now, we are only left with 2000 bananas, and taking it to W,
As we are only left with 2000 bananas, we can make a maximum of 2 trips forward, and 1 trip backward.
Q<-----3Y------>W
It can be understood as we have only 2000 bananas left, and the camel can take 1000 bananas a time.
Let's find the distance with the Equation,
2000-3Y=1000
So, Y=333. But as the Camel is eating 1 banana per km,so, it can't be in fraction,
thus, Y=333
As we reduced the term,
so, will increase 1 banana,i.e, 1000+1=1001.
Again,there will only be 1 last trip, with the remaining distance,
1000-200-333=467.
So, Remaining Distance=467.
And 1000-467=533
Thus, total Bananas reached at destination=533.
Answer->533