" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2024 KUDO.TIPS - All rights reserved.
beda = b = 3
Un = a +(n-1)b
Un = 20 + (n-1)3
Un = 20 + 3n - 3
Un = 17 + 3n
U30 = 17 + 3n
U30 = 17 + (3 x 30)
U30 = 17 + 90
U30 = 107
maka banyak kursi di deret ke 30 = 107 buah
b = 3
Sn = 30
Sn = n/2 (a +Un)
Sn = 30/2 (20 + 107)
= 15 (127)
= 1907 U30 = a+29b= 20 +29(3) = 20 +87 = 107