Airplanes Meeting Distance

An airplane flew from city A to city B at a speed of 500 km/h. Fifteen minutes later, an airplane took off from city B to city A at a speed of 450 km/h. After 45 minutes, the planes met. Determine the distance between A and B.

Final Answer:

s =  600 km

Step-by-step explanation:

$$\begin{gathered} v_1=500\text{km/h} \\ {v}_2=450\text{km/h} \\ {t}_2=15/60=\frac{1}{4}=0.25\text{h} \\ {t}_1=45/60=\frac{3}{4}=0.75\text{h} \\ s=v_1\cdot t_1+v_2\cdot (t_1-t_2)=500\cdot 0.75+450\cdot (0.75-0.25)=600\text{km} \end{gathered}$$

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