A boy wrote successive whole numbers starting from 1 up to 800. In doing so, how many times did he write the digit 8

A boy wrote successive whole numbers starting from 1 up to 800. In doing so, how many times did he write the digit 8?

(a) 160

(b) 161

(c) 152

(d) 260

Sol:

In line ⊣ 8, 18, 28, —- 98 = 10 × 8 = 80

In line ⊣ 80, 81, 82, ——89 ⇒ 10 × 8 = 80

And Iine 800 = 1

⇒ 80 + 80 + 1 = 161