Question

The number of numbers that lie
between 500 and 600 whose digit
in the units place is same as the
digits in the tens place (including
both 500 & 600) is ............
A) 14
B) 13
C) 12 D) 11
( )​

Answer 1

Answer:

13

Explanation:

13 is the answer because we have to include both

Answer 2

Since, we are concerned about numbers between 500 and 600; so, there is no point 9 can be placed in hundred’s place.

For ‘9’ in unit’s place:

The ten’s place can be filled up using 0, 1, 2, 3, 4, 5, 6, 7 and 8; i.e., in 9 ways.

Here, we can’t consider ‘9’ for ten’s place; as the condition is prohibiting us.

For ‘9’ in ten’s place:

The unit’s place can be filled up using 0, 1, 2, 3, 4, 5, 6, 7 and 8; i.e., in 9 ways.

Here, we can’t consider ‘9’ for unit’s place; as the condition is prohibiting us.

So, the answer is (9 + 9) = 18. There are 18 numbers between 500 and 600 in which 9 occurs only once as a digit.