Correct Answer - Option 1 : 792
Concept used:
The set of numbers {1, 2, 3, 4,.........} are called the natural numbers.
Calculation:
From 1 to 9,
The total numbers = 9
So,
Number of times key buttons of typewriter pressed = 9 ----(1)
From 10 to 99,
Total numbers = 90
Each number has 2 digits, so
⇒ Number of times key buttons of typewriter pressed = 2 × 90
⇒ Number of times key buttons of typewriter pressed = 180 ----(2)
From 100 to 300,
The total numbers = 201
Each number has 3 digits, so
⇒ Number of times key buttons of typewriter pressed = 201 × 3
⇒ Number of times key buttons of typewriter pressed = 603 ----(3)
Now, The total number of times key pressed on the typewriter,
⇒ 9 + 180 + 603
⇒ 792
∴ 792 times the key of a typewriter has to be pressed in order to type the first 300 letters.
