Step 1: Number of Ways to Select 4 Men from 10.
The number of ways to select 4 men from 10 is given by the combination formula:
\[
C(n, r) = \frac{n!}{r!(n - r)!}
\]
Substituting \( n = 10 \) and \( r = 4 \):
\[
C(10, 4) = \frac{10!}{4!(10 - 4)!} = \frac{10 \times 9 \times 8 \times 7}{4 \times 3 \times 2 \times 1} = 210
\]
Step 2: Conclusion.
Thus, the number of ways to divide the 10 men into two groups of 4 and 6 is 210.
Final Answer: \[ \boxed{210} \]
Let R = {(1, 2), (2, 3), (3, 3)}} be a relation defined on the set \( \{1, 2, 3, 4\} \). Then the minimum number of elements needed to be added in \( R \) so that \( R \) becomes an equivalence relation, is: