Question

Tentukan jumlah dari semua bilangan ganjil dua digit

Answer 1

Verified answer

Bilangan ganjil 2 digit :
11 + 13 + ... + 99 = Sn
n = (Un - a)/b + 1
n = (99 - 11)/(13 - 11) + 1
n = 88/2 + 1
n = 45

Sn = (n/2)(a + Un)
S45 = (45/2)(11 + 99)
S45 = 45 × 55
S45 = 2475

Jumlah smua bil ganjil 2 digit = S45 = 2475