" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2025 KUDO.TIPS - All rights reserved.
Un=a+(n-1)b
297=102+(n-1)3
297-102=(n-1)3
195=(n-1)3
n-1=195/3
n-1=65
n=65+1=66
Sn=66/2(102+297)=33(399)=.....