Question

How many times would the digit 6 be used in numbering a book of 639 pages ?

Answer 1

Answer:

Step-by-step explanation:

though combinations method can be used, I used a different approach that helped me solve this in less than a minute. A close look at the options tell us that A is too much. E is too Less. Now,

There are 100 numbers which begin with 600

Next, In every 10 numbers such as 100 to 110, 110 to 120, 120 to 130 6 comes at least once. Number of such intervals = End limit - First no. / interval. Our range of numbers is 100 - 1000

1000 - 100 = 900/10 = 90

Number of 10s interval in this is 90. So 90 '6s'

So far we have calculated 190.

Now, 60 - 69 is the tens interval that has 11 '6s'  66 has two '6s), 1 of which has been counted in the previous step. And there are 9 such intervals (160 to 169, 260 to 269, 360 to 369, ,960 to 969) This gives us another 90 '6s'

The total now comes to 280. The nearest to which is 300.