(A) KBirds are flying in the pattern like 1 in the first row, 3 in the

1.	(A) KBirds are flying in the pattern like 1 in the first row, 3 in the eand so on. Making total 20 rows as per the figure given belo itotal number of birds.43.) A student named Akash is observing birds tlying in the sky nate second(B) 400(C) 40(D) 200(A) 39
Answer» This is an APwhere a= 1 d= 2n= 20Sn= n/2(2a+(n-1)d) = 10(2+38) = 400 thanks

(A) KBirds are flying in the pattern like 1 in the first row, 3 in the eand so on. Making total 20 rows as per the figure given belo itotal number of birds.43.) A student named Akash is observing birds tlying in the sky nate second(B) 400(C) 40(D) 200(A) 39

Answer»

This is an APwhere a= 1 d= 2n= 20Sn= n/2(2a+(n-1)d)

= 10(2+38)

= 400

thanks