Answers

2015-02-08T12:39:25+05:30

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
sum of 1st 40 natural numbers is
                                 = n(a+l)/2
                                 = 40(1+40)/2
                                 = 40×41/2
                                 = 20×41
                                 = 820
                    
0
2015-02-09T16:15:31+05:30
Sum of first n natural numbers =  \frac{n(n+1)}{2}
                                             
sum of first 40 natural numbers =  \frac{40(40+1)}{2}
        
                                               = 20 × 41
 
                                               = 820
0