Reply To: The Riddle Thread….

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1) What was the answer?

2) What was the student’s “trick”?

3) Who was the student?

1) 5,050

2) There are 100 integers, 1 through 100. Add the first and last => 1 + 100 = 101. Add the second and second to last => 2 + 99 = 101. Continue the process until the fiftieth and fiftieth to last => 50 + 51 = 101. Therefore we have 50 pairs of 101. 50 x 101 = 5,050. In general to add the integers 1 through n the formula is (n/2)*(n+1) or more commonly written as (n*(n+1))/2. (This works for all n where n can be odd or even.)

3) If I remember correctly the student was Carl Friedrich Gauss who lived in the late 1700s to mid 1800s.

Good night everyone