Find the sum of all integers between 100 and 550, which are multiples of 9.
a = 108
L = 549
D = 9
549 = 108 + (n - 1)9
549 = 99 + 9n
9n = 450
n = 50
Sn= 
[216 + 49 (9)]
= 16425
18
Find the sum of all integers between 100 and 550, which are multiples of 9.
a = 108
L = 549
D = 9
549 = 108 + (n - 1)9
549 = 99 + 9n
9n = 450
n = 50
Sn= [216 + 49 (9)]
= 16425