Students Subjects D4Ef99
1. **Problem statement:** Among 100 students, (75 - x) study physics, (50 - x) study accounts, and 25 study neither. No student studies both subjects. Find the value of $x$, the number studying physics, and the number studying accounts.
2. **Understanding the problem:** Since 25 students study neither subject, the remaining students studying either physics or accounts are $100 - 25 = 75$.
3. **Key rule:** No student studies both subjects, so the sets are disjoint. Therefore, the total number studying physics plus the total number studying accounts equals 75.
4. **Set up the equation:**
$$ (75 - x) + (50 - x) = 75 $$
5. **Simplify:**
$$ 75 - x + 50 - x = 75 $$
$$ 125 - 2x = 75 $$
6. **Solve for $x$:**
$$ 125 - 2x = 75 $$
$$ -2x = 75 - 125 $$
$$ -2x = -50 $$
$$ x = \frac{-50}{-2} = 25 $$
7. **Find the number studying physics:**
$$ 75 - x = 75 - 25 = 50 $$
8. **Find the number studying accounts:**
$$ 50 - x = 50 - 25 = 25 $$
**Final answers:**
- $x = 25$
- Number studying physics = 50
- Number studying accounts = 25