Question

Deret aritmatika jumlah bilangan yang bukan kelipatan 3 antara 200 dan 400?

Answer 1

U1 = 201
b = 3
Un = 3n + 198
3n + 198 = 399
n = 201/3 = 67
s67 = 67/2 x (200+400) = 67 x 300 = 20.100

u1 = 201
b = 1
un = 200+n
399 = 200+n
n = 199
s199 = 199/2 x (200+400) = 199 x 300 = 59.700

yg bukan kelipatan 3 = 59.700 - 20.100 = 39.600