There are 7 paintings in a row. How many ways are there in which there...
Understanding the ProblemTo solve the problem of arranging 7 paintings with a specific painting (let's call it P1) on either side of another specific painting (let's call it P2), we need to consider the positions and arrangements carefully.
Step 1: Fixing the Positions of P1 and P2- We want P1 to be on one side of P2.
- The arrangement can be visualized as P1, P2, and a space for the other 5 paintings.
Step 2: Arrangement of Remaining Paintings- Let's denote the remaining paintings as P3, P4, P5, P6, and P7.
- We can represent the arrangement as P1, P2, and the 5 remaining paintings.
Step 3: Counting Arrangements- First, we can position P1 and P2 together in a block. This block can be arranged as (P1, P2) or (P2, P1), giving us 2 arrangements.
- The remaining 5 paintings can be arranged in the remaining 5 positions.
Calculating Total Arrangements- The total number of arrangements for the 5 remaining paintings is 5! (5 factorial).
- Therefore, the total arrangements can be calculated as follows:
- Arrangements of P1 and P2: 2
- Arrangements of remaining paintings: 5! = 120
- Finally, the total number of ways = 2 * 120 = 240.
Final AnswerIn conclusion, the total number of ways to arrange 7 paintings with a specific painting on either side of another specific painting is
240.