\[ \frac{1}{9!}+\frac{1}{10!} = \frac{11\cdot10}{11!}+\frac{11}{11!} = \frac{121}{11!} \;\Rightarrow\; x=121 \] ✅ Answer: \(x=121\)

We have 5 consonants and 4 vowels. We need to form a word with 3 consonants and 3 vowels.

Step 1: Choose consonants

\[ \binom{5}{3} = 10 \]

Step 2: Choose vowels

\[ \binom{4}{3} = 4 \]

Step 3: Arrange the chosen 6 letters

\[ 6! = 720 \]

Step 4: Total words

\[ 10 \times 4 \times 720 = 28800 \]

Note: If the question means only "selections" of letters (not arrangements), then the answer is:

\[ \binom{5}{3}\times \binom{4}{3} = 10 \times 4 = 40 \]

Final Answer:

- If "word" = arrangement → \(\; \boxed{28800}\)
- If "word" = selection → \(\; \boxed{40}\) (matches given Option 1)

Solution:

Number of straight lines from \(n\) points (no three collinear) is \(\binom{n}{2}\).

Here, \(n = 15\).

\[ \binom{15}{2} = \frac{15 \times 14}{2} = 105 \]

Adjustment for collinearity:
Out of 15 points, 5 are collinear.
Lines from these 5 points = \(\binom{5}{2} = 10\).
But actually they form only 1 line.
Extra counted = \(10 - 1 = 9\).

Correct total lines:

\[ 105 - 9 = 96 \]

Final Answer: The total number of straight lines formed = 96

Case 1: All persons are distinct

For n distinct persons around a round table (rotations same), arrangements = \((n-1)!\).

Here, \(n=9\). So arrangements = \((9-1)! = 8! = \boxed{40{,}320}\).

Case 2: Persons are identical by nationality

If 4 Indians, 3 Americans, and 2 Britishers are considered identical within their groups, then

Arrangements = \[ \frac{(n-1)!}{4!\,3!\,2!} = \frac{8!}{4!\,3!\,2!} = \boxed{140}. \]

Short Solution:

Total people = 4 Indians + 3 Americans + 2 Britishers = 9
Since arrangement is around a circular table, we fix one position ⇒ remaining to arrange: 8 positions

Group the 3 Americans together as a single unit ⇒ total units = 4 Indians + 1 American group + 2 Britishers = 7 units
Circular arrangement of 7 units = \( (7 - 1)! = 6! \)

Internal arrangements of 3 Americans = \( 3! \)

Total arrangements =
$$6! \times 3! = 720 \times 6 = \boxed{4320}$$