A person put one coin at 1’O clock, two coins at 2’O clock, 3 coins at 3°O clock and so on in a box.Then the number of coins he has put in the box between 6:30 am to 6:30pm in a day is
From 7AM to 6PM, all numbers from 1 to 12 would have been come across by.
So the total is = 1+2+3....+11+12 = 78
Create a FREE account and get: