Time remaining:
gauss approach using n/2

label Algebra
account_circle Unassigned
schedule 0 Hours
account_balance_wallet $5

1+3+5+7+...999

Nov 26th, 2014

Notice that 1 + 999 = 1000, 3 + 997 = 1000, 5 + 995 = 1000, etc. 

You have to figure out how many pairs there are in your sum.  We can figure this out if we take 1-99 and then extrapolate.  Since there are 100 number is 1-100, there would be 50 number in 1-100 odd; we're pairing 2 numbers of the 50, so we would have 25 pairs of numbers in 1-100.  If we multiply that by 10 (because we're looking at 1-1000, not 1-100), we would have 2500 pairs of numbers that add up to 1000.

Therefore, we take 2500*1000 = 2,500,000


Hope this helps!

Nov 26th, 2014

Studypool's Notebank makes it easy to buy and sell old notes, study guides, reviews, etc.
Click to visit
The Notebank
...
Nov 26th, 2014
...
Nov 26th, 2014
Jun 29th, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer