The number / character present in any particular situation is called the number of cards / letters. These types of questions are usually asked in all examinations. In this type of question a series of numbers / letters has been given, which according to the prescribed conditions given in the question to the testers, is to find the total number of that number / character, finding a particular particular number / character. Two types of questions are asked under this test.
Under the number series , such questions are asked which are related to the points series which are to be known according to any condition.
Example: How many such are the numbers in the series of the following, 7 right before, but not immediately after 5?
7 8 3 7 8 5 1 2 7 8 3 3 4 7 8 2 5 6 6 8 3
(a) one (b) two (c) three (d) four
Solution: (c) According to the question, there are three 8 in the series, whose 7 are right before but 5 later in the future.
Based on the alphabetical series , such well-formed questions are asked which are related to the letter chain which must be known according to a condition.
Example: How many K are there in the series of the following letters after which T comes but N comes out just before?
Z K T L K N K T F G Z H K T K N G H J L N K T T
(a) None (b) one
(c) two (d) three (e) more than three
Solution: (c) According to the question, there are two K in series, after which T comes, but N does not come right before.
Under the Mixed Question , a number or five / six / seven numbers are added which, after rearranging the terms given in question, have to know the answer.
Example 1. The number of first and fifth digits is mutually changed in number 89123647. Similarly, the places of second and sixth and subsequent points are also mutated. Which of the following will be the fourth digit from the right edge of the rearrangement?
(a) 8 (b) 8 (c) 1 (d) 2 (e) None of these
Solution: (b) Number given = 89123647
New number created after change = 36478912
So the fourth digit from the right is 8.
Example 2. Number 6492758 should be decorated in ascending order, how many digits will remain unchanged?
(a) one (b) two (c) three (d) none of these
6 4 9 2 7 5 8
2 4 5 6 7 8 9
Hence the points of two digits 4 and 7 will remain unchanged.
Example 3. How many pairs of digits are there in number 561234, among which there are as many numbers in the number as if to arrange the digits in ascending order?
(a) None (b) one (c) two (d) three (e ) More than three
Solution: (e) More than three
Example 4. The second and third digits of each of the numbers given below are converted into each other. Then the first and last digits of the new numbers are converted into one another. Now what is the largest number of those five numbers?
184 372 526 438 273
(a) 184 (b) 372 (c) 526 (d) 438 (e) 273
Resolution: (a) 184 ⇒ 148, 372 ⇒ 327, 526 ⇒ 562, 438 ⇒ 483, 273 ⇒ 237
Re: on mutual change of first and last digits of new numbers
148 ⇒ 841, 327 ⇒ 723, 562 ⇒ 265, 483 ⇒ 384, 237 ⇒ 732
So the largest number = 841 i.e. 184
Example 5. If numbers are numbered 1 to 30, the numbers which contain only one number is ‘2’ and those which are divided by 2, then how many remaining numbers will be left?
(a) 12 (b) 14 (c) 13 (d) 10
Solution: (d) The total numbers from 1 to 30 are as follows
Total number divided by a number 2 and 2 = 20
Thus the remaining numbers = 30 – 20 = 10