If all the numbers between 11 and 100 are written on a piece of paper. How many times will the number 4 be used?
Choose the correct answer.
A) 87  B) 267  C) 68  D) 26  E) 21
We have to consider the number of 4's in two digit numbers. _ _   If we fix 4 in the 10th place, unit place be filled with 10 ways. If we fix 4 in units place, 10th place be filled with 9 ways (0 is not allowed)   So total 19 ways.   87lternatively:   87nswer:87
<result>A</result>
If all the numbers between 11 and 100 are written on a piece of paper. How many times will the number 4 be used?