I have always had the correct number of candles on each of my birthday cakes. I have had exactly one birthday cake for each year of my life. If I have blown out a total of 861 candles thus far, how old am I?
Can you find the answer without just adding up numbers until you reach 861?
Answer
41
If n = 41 , we see that:
S = 41(41+1)/2 = 41(42)/2 = 861.
Thus, if you add up the integers from 1 to 41, you will get a total of 861.
