26. 一只野兔逃出80步后猎狗才追它，野兔跑 8步的路程猎狗只需跑3步，猎狗跑4步的时间兔子能跑9 步。猎狗至少要跑多少步才能追上野兔?
解：狗跑12步的路程等于兔跑32步的路程，狗跑12步的时间等于兔跑27步的时间。所以兔每跑27步，狧追上5步（兔步），狗要追上80步（兔步）需跑[27× $(80 \div 5) + 80] \div 8 \times 3 = 192$ (步）。
27.甲、乙两人在铁路旁边以同样的速度沿铁路方向相向而行, 恰好有一列火车开来, 整个火车经过甲身用了18秒，2分后又用15秒从乙身边开过。问：
(1) 火车速度是甲的速度的几倍?

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4. Final Answer: $\frac{20}{17}$ times A's speed

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Step 1 ：1. Set up the equation to find the relationship between the distance the train travels in 18 seconds and 15 seconds: $\frac{d i s t a n c e_{t r a i n_{18 s}}}{d i s t a n c e_{t r a i n_{15 s}}} = \frac{18 \times s p e e d_{t r a i n}}{15 \times s p e e d_{t r a i n}}$

Step 2 ：2. Simplify the equation to find the relationship between the train's speed and A's speed: $\frac{d i s t a n c e_{t r a i n_{120 s}}}{d i s t a n c e_{A_{120 s}} + d i s t a n c e_{t r a i n_{18 s}}} = \frac{120 \times s p e e d_{t r a i n}}{120 \times s p e e d_{A} + 18 \times s p e e d_{t r a i n}}$

Step 3 ：3. Solve the simplified equation to find the relationship between the train's speed and A's speed: $\frac{20 \times s p e e d_{A}}{17 \times s p e e d_{t r a i n}}$

Step 4 ：4. Final Answer: $\frac{20}{17}$ times A's speed

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