Q8). In a row of students, Amit is 7th from the left while Jagmohan is 18th from right. Both of them interchange their positions such that Amit becomes 21st from the left. How many people are there in the row?
According to question
Original Place of Jagmohan = Place of Amit after Interchange
Amit’s Position from Right = 18th
Amit’s Position from Left = 21st
Total no of student = 18 + 21 - 1 = 38
Q9). In a row of students, A is 10th from the left and B is 5th from the right. If both interchange their place and new position of A is 15th from left. New position of B from right will be?
After Interchange Position of A = Original Position B
A Left = 15
A right = 5
Total Students = 15 + 5 - 1 = 19,
New Position of B from left = 10th.
Total Student = 19.
Position of B from right = 19-10+1 = 10th.
Overlapping Problems (Q 10 – Q13) :
Q10). In a row, position of A from left side of the row is 15th and position of B from right side of the row is 6th, find the total number of students in the row.
Q11). In a row, position of A from the left side of the row is 15th and position of B from the right side of the row is 6th. If there are 3 boys between A and B, find total no. of students.
Q12). In a row, A is 6th from the left end and B is 10th from the right end in a row of boys. If there are 8 boys between A & B, how many boys are there in the row?
Q13). If position of A from the left side of a row is 15th and position of B from right side of a row is 19th and three persons are sitting in middle of A and B. Find the maximum number of person that can be seated in this row.
Generally, to find minimum number we use Overlapping case and in Maximum number we use straight forward case
Case 1: Overlapping
Number of persons b/w A and B = 3
Minimum number of person = 15 + 19 - (3 + 2) = 29
Case 2: No Overlapping (Straight Forward Case)
Number of persons between A and B = 3
Maximum number of person = 15 + 19 +3 =37