Mastering Mental Ability:Number Ranking

Order and ranking involves the arrangement of position of an object or a person from left to right or from top to bottom. Now let's discuss some questions on order and ranking and some shortcuts to solve them.

Questions and Answers

1. In a row of students, the position of Jennifer from the left side of the row is 17, and her position from the right end is 44. Find the total number of students in the row.

To determine the total number of students in the row, we can use the information given about Jennifer's position from both ends of the row:

• 1. Jennifer's position from the left side: 17
• 2. Jennifer's position from the right side: 44

We can sum these positions and subtract 1 (since Jennifer is counted in both positions):

2. Here are 64 history books arranged from top to bottom in a library. Ancient history is 25th from the top end, and medieval history is 30th from bottom end. What is the total number of books between ancient and medieval history?

To determine the total number of books between the ancient history book and the medieval history book, we first need to find their positions in the sequence:

Position of the Ancient History Book:

Given that the ancient history book is 25th from the top, its position is 25.

Position of the Medieval History Book:

Given that the medieval history book is 30th from the bottom, we can find its position from the top by subtracting 30 from the total number of books (64) and then adding 1:

Position from bottom + 1 = 64 - 30 + 1 = 35

Number of Books Between the Ancient and Medieval History Books:

The number of books between the ancient history book (25th) and the medieval history book (35th) is calculated by subtracting the position of the ancient history book from the position of the medieval history book and then subtracting 1 (since we don't count the books themselves):

Number of books between=35-25-1=9

Therefore, there are 9 books between the ancient and medieval history books.