Question:

The number of ways of forming a queue of 4 boys and 3 girls such that all the girls are not together, is:

Updated On: Apr 10, 2026
  • 5040
  • 3050
  • 3410
  • 4320
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation


Step 1: Understanding the Concept:
The phrase "all the girls are not together" means we subtract the cases where all 3 girls form a single block from the total possible arrangements of 7 people.

Step 2: Key Formula or Approach:
Number of ways = (Total arrangements) $-$ (Arrangements where all girls are together).

Step 3: Detailed Explanation:
1. Total arrangements: 7 people can be arranged in $7!$ ways. \[ 7! = 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1 = 5040 \] 2. Girls together: Treat the 3 girls as a single unit (G). Now we have 4 boys + 1 unit = 5 units to arrange. - Number of ways to arrange these 5 units = $5!$. - The 3 girls can be arranged among themselves in $3!$ ways. \[ \text{Together ways} = 5! \times 3! = 120 \times 6 = 720 \] 3. Required ways: \[ 5040 - 720 = 4320 \]

Step 4: Final Answer:
The number of ways is 4320.
Was this answer helpful?
0
0