jumlah bilangan kelipatan 4 antara 200 dan 400

14700

dik : 204, 208, 2012.... 392, 396
a = 204
b = u2-u1 = 208 - 204 = 4
un = 396

un = a + (n-1) b
396 = 204 + (n-1) 4
396 = 204 + 4n - 4
-4n = 204 - 4 - 396
-4n = -196
n = -196/-4
n = 49

totalnya
sn= n/2 (2a + (n-1) b)
sn= 49/2 (2.204 + (49-1) 4)
sn= 49/2 (408 + 196 - 4)
sn= 49/2 (600)
sn= 14.700

ket: a= bilangan awal
b= beda (u2-u1)
un= nilai akhir