SOLUTION: find the least number of term of the A.P 1+3+5... that are required to make a sum exceeding 4000

The given sum is the sum of the first n positive odd integer numbers from 1 to 2n-1


    S = 1 + 3 + 5 + . . . + (2n-1).


It is well known fact that this sum is equal to .


So, the problem asks to find  "n"  such that


     > 4000.


Notice that   = 63.25 (approximately).


Therefore, the required value of n is 64.   


ANSWER.  The least number of "n" is 64.