1. **State the problem:** We need to find the price of an adult's ticket and a child's ticket given two total fare amounts for different group sizes.
2. **Set variables:** Let $a$ be the price of an adult ticket and $c$ be the price of a child's ticket.
3. **Write equations from the problem:**
- For 3 adults and 4 children: $$3a + 4c = 98$$
- For 2 adults and 3 children: $$2a + 3c = 69$$
4. **Solve the system of equations:**
Multiply the second equation by 3 and the first by 4 to align coefficients of $c$:
$$4(3a + 4c) = 4 \times 98 \Rightarrow 12a + 16c = 392$$
$$3(2a + 3c) = 3 \times 69 \Rightarrow 6a + 9c = 207$$
5. **Subtract the second from the first:**
$$ (12a + 16c) - (6a + 9c) = 392 - 207 $$
$$ 6a + 7c = 185 $$
6. **Express $a$ in terms of $c$:**
$$ 6a = 185 - 7c $$
$$ a = \frac{185 - 7c}{6} $$
7. **Substitute $a$ into one original equation, e.g., $2a + 3c = 69$:**
$$ 2 \times \frac{185 - 7c}{6} + 3c = 69 $$
8. **Multiply both sides by 6 to clear denominator:**
$$ 2(185 - 7c) + 18c = 414 $$
$$ 370 - 14c + 18c = 414 $$
$$ 370 + 4c = 414 $$
9. **Solve for $c$:**
$$ 4c = 414 - 370 $$
$$ 4c = 44 $$
$$ c = 11 $$
10. **Find $a$ using $a = \frac{185 - 7c}{6}$:**
$$ a = \frac{185 - 7 \times 11}{6} = \frac{185 - 77}{6} = \frac{108}{6} = 18 $$
**Final answer:**
- Adult ticket price $a = 18$
- Child ticket price $c = 11$
Train Fare B176Bb
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