In a row of 20 students facing North, R is 9th from the left end. How many students are there between R and S?Choices:- 7 8 9 10

1. Break Down the Problem

• We know R is the 9th student from the left in a row of 20 students.
• We need to find how many students are there between R and S.

2. Relevant Concepts

• Since R is 9th from the left, there are 8 students to the left of R.
• The total number of students is 20, so there are $20 - 9 = 11$ students to the right of R.

3. Analysis and Detail

• The question does not specify the position of S, so we will consider two possible scenarios:
  1. Scenario 1: If S is to the right of R.
  2. Scenario 2: If S is to the left of R.

For Scenario 1 (S is to the right of R):

• If S is the next student after R, then no students are between them (0).
• If S is the 10th student, there will be 0 students between them.
• If S is the 11th student, there is 1 student between R and S.
• If S is the 12th student, there are 2 students between R and S.
• Continuing this way, if S is the 19th student, there are 9 students between R and S.

For Scenario 2 (S is to the left of R):

• If S is the 8th student, then there are 0 students between R and S.
• If S is the 7th student, there is 1 student between R and S.
• If S is the 6th student, there are 2 students between R and S.
• Continuing this way, if S is the 1st student, there are 8 students between R and S.

4. Verify and Summarize

• Based on the value of S, the number of students between R and S can vary between 0 to 9.
• Considering the choices provided (7, 8, 9, 10), the only fitting choice we can summarize from our analysis is 8 or 9 depending on the position of S.

Final Answer

If S is 1st, there are 8 students between R and S. Hence, the answer from the choices given is 8.