You are depositing Rs. 3 in First day and Rs. 3 in Second day in your account. And you are withdrawing Rs. 4 from your account in Third day. You do this repeatedly. When soon do you have Rs. 60?
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Thus you would have reached Rs. 60 in (60/2)*3 = 90 days, but important thing to notice is that you are withdrawing Rs. 4 on every third day so your balance will reach Rs.60 mark earlier than that.
So, if we observe we will reach (60-6)=Rs.54 in (54/2)*3=81 days, and as you will deposit Rs.6 in next two days, you will reach Rs.60 in 83days.