<span>As far as i know it is related to Gauss.
Write the sequences forward and backward first.
1 +2 +3 +.....+1002
1002+1001+1000+.....+1
--------------------------------------... Adding them
1003+1003+......(1002 times)
=1002x1003
But this contains the series twice.
So, the sum is = 1002x1003/2=501x1003=502503. answer</span>
Answer:
Step-by-step explanation:
Well, ithe measure is 8, or u have to use examples to solve
Answer:

Step-by-step explanation:

It will take them 20 hours, since the question is asking how long it will take them when working together you add each of their hours together,9+11=20