Que: Find the number of keystrokes required to type numbers from 1 to 900?
(A) 2,583
(B) 2,589
(C) 2,590
(D) 2,592
(E) 2,593
Que: Find the number of keystrokes required to type numbers from 1 to 900?
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- Max@Math Revolution
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Solution: The number range is from 1 to 900.
One digit numbers = 1 to 9 = 9 [Will need 1 key stroke each] = 9 key strokes
Two digit numbers = 10 to 99 [Will need 2 key stroke each] = 90 * 2 = 180 key strokes
Three digit numbers = 100 to 900 [Will need 3 key stroke each] = 801 * 3 = 2403 key strokes
Total keystrokes = 9 + 180 + 2403 = 2592
Therefore, D is the correct answer.
Answer D
One digit numbers = 1 to 9 = 9 [Will need 1 key stroke each] = 9 key strokes
Two digit numbers = 10 to 99 [Will need 2 key stroke each] = 90 * 2 = 180 key strokes
Three digit numbers = 100 to 900 [Will need 3 key stroke each] = 801 * 3 = 2403 key strokes
Total keystrokes = 9 + 180 + 2403 = 2592
Therefore, D is the correct answer.
Answer D
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