in how many different ways can 8 examination papers be arranged in a row, so that the best and the worst papers may never come together?
The number of ways is 30240.
Quick Scoop: Arranging 8 Examination Papers
Final Answer
In how many different ways can 8 examination papers be arranged in a row, so
that the best and the worst papers may never come together?
→ 30240 ways.
Step-by-step idea (short and clear)
- Total arrangements without any restriction
There are 8 distinct papers, so total arrangements:
8!=403208!=403208!=40320
- Arrangements where best and worst are together
- Treat “best + worst” as one block.
- Then we have 7 units (this block + 6 other papers).
- These 7 units can be arranged in 7!7!7! ways.
* Inside the block, “best, worst” can be ordered in 2!2!2! ways (BW or WB).
So, arrangements with best and worst together:
7!×2!=5040×2=100807!\times 2!=5040\times 2=100807!×2!=5040×2=10080
- Arrangements where they are never together
8!−(7!×2!)=40320−10080=302408!-(7!\times 2!)=40320-10080=302408!−(7!×2!)=40320−10080=30240
Tiny “story” way to remember it
Think of 8 papers marching in a line.
First count all possible marching orders.
Then count the “bad” ones where the best and worst are handcuffed
together as a single pair.
Subtract those “handcuffed” orders from the total, and you’re left with only
the good ones — where they never stand side by side.
HTML table summary
html
<table>
<tr>
<th>Quantity</th>
<th>Expression</th>
<th>Value</th>
</tr>
<tr>
<td>Total arrangements of 8 papers</td>
<td>8!</td>
<td>40320</td>
</tr>
<tr>
<td>Arrangements with best & worst together</td>
<td>7! × 2!</td>
<td>10080</td>
</tr>
<tr>
<td>Arrangements where they never come together</td>
<td>8! − (7! × 2!)</td>
<td><strong>30240</strong></td>
</tr>
</table>
TL;DR:
Number of arrangements where the best and worst papers never come together =
30240.
Information gathered from public forums or data available on the internet and portrayed here.