if all the numbers from 1 to 150 are to be typed using a keyboard , the keys of the key board should be pressed how many times
Answers
Answer:
Step-by-step explanation:
792 times should the keys of a keyboard be pressed in order to type the first 300 counting numbers.
Step-by-step explanation:
To find : How many times should the keys of a keyboard be pressed in order to type the first 300 counting numbers?
Solution :
The numbers are from 1, 2, 3 ... 300.
From 1 to 9,
The keyboard pressed 9 times.
From 10 to 99,
The keyboard pressed 2\times (99-10+1)2×(99−10+1) times
The keyboard pressed 180 times.
From 100 to 300,
The keyboard pressed 3\times (300-100+1)3×(300−100+1) times
The keyboard pressed 603 times.
Total number of times the keyboard pressed is
n= 9 + 180 + 603n=9+180+603
n= 792n=792
Therefore, 792 times should the keys of a keyboard be pressed in order to type the first 300 counting numbers.
Answer:
342 times
Step-by-step explanation:
Given :- The given range of number = 1 to 150.
To Find :- Number of times keys of keyboard will be pressed to type numbers from 1 to 150.
Solution :-
The range of number = 1, 2, 3, ........, 150
For number from 1 to 9, the keys will be pressed 9 times.
For numbers from 10 to 99, for each number, keys will be pressed twice.
The number of numbers from 10 to 99 = 99 - 9 = 90
∴ Number of times keys will be pressed for numbers from 10 to 99
= 2 × 90 = 180 times.
For numbers from 100 to 150, for each number, keys will be pressed thrice.
The number of numbers from 100 to 150 = 150 - 99 = 51
∴ Number of times keys will be pressed for numbers from 100 to 150
= 3 × 51 = 153 times.
Therefore, Total number of times keys are pressed = 9 + 180 +153
= 342 times.
#SPJ2
https://brainly.in/question/1612019
https://brainly.in/question/18942499