+0  
 
-1
14
1
avatar+1839 

Find the greatest prime divisor of the value of the arithmetic series
1 + 2 + 3 + \dots + 135 + 136 + 137 + 138 + 139 + 140.

 Jun 16, 2024
 #1
avatar+42 
0

Using the arithmetic series formula, we find the sum is \(\frac{(140+1)(70)}{2}\), which is 141*35. Now that we have a factorization, we can easily find the greatest prime divisor. The prime factorization is 3*5*7*47, so the greatest prime divisor is \(47\).

 

Feel free to tell me if I did anything wrong! :D

 Jun 19, 2024

3 Online Users

avatar