GMAT Problem Solving (PS) | Re: The number of water lilies on a certain lake doubles every

I thought this way :
30 days will take to complete the pond with lillies count as 2^30 (since it takes 2 days to double hence will take 30 days of 60)
on first day - 2^0 =1 lilly
on day 2 - 2^1 = 2
on day 3 - 2^2 = 4 so on ...
now since the there are two lillies already it will take 2^30/ 2^1 = 2^29 ...this will take complete 2* 29 days i.e 58 days

I hope it is clear .....

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