Question

In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake?

Answer 1

The day before it is full it will be half full ( bacuse it doubles in size every day)

So the answer is 47 days

Answer 2

see the plants grow in airthemetic progression.
day 1 its is 1 and day 2 it is 2, day 3 it is 4.......
so,
1,2,4,6,8,......
so it take 48 days to fill the pond..
total plants = 48/2(2*1+(48-1)*2)
total plants= 2304
so half the plants is 1152
so,
1152=n/2(2*1+(n-1)2)
n=47
it so 47 days to complete half the pond.