How many times the keys of a typewriter have to be pressed in order to write numbers from 121 to 1346?
Total numbers between 121 to 999
= $$999-121+1=879$$
Since, these are 3 digit numbers, thus to type each number key is pressed 3 times
Thus, keys pressed while writing numbers from 121 to 999 = $$879\times3=2637$$
Similarly, numbers between 1000 to 1346
= $$1346-1000+1=347$$
Keys pressed = $$347\times4=1388$$
$$\therefore$$ Total times the keys are pressed = $$2637+1388=4025$$
=> Ans - (D)
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