Two trains each make a journey of 330km. One of the train travels 5km/h faster than the other and takes 30 min less time. Find the speed of the trains

Question

dan815 · Answer

read that wwrong lol

whpalmer4 · Answer

train 1 has speed $s_1$.  train 2 has speed $s_2 = s_1+5$.  train 1 takes time $t_1$ to travel 330 km.  train 2 takes time $t_2 = t_1-\frac{1}{2}$ to travel 330 km.

$d = st$ is the formula for distance traveled in time $t$ at speed $s$. We can write two equations for the trains:

$$330 \text{ km} = s_1*t_1$$$$330 \text{ km} = s_2*t_2 = (s_1+5)*(t_1-\frac{1}{2})$$

whpalmer4 · Answer

Solve those two for $s_1,t_1$ and then use the relationship between $s_1,s_2$ to get the other train's speed.

dan815 · Answer

t*(x+5)=330 = x*(t+0.5)
note the 30 mins became 0.5 hours

whpalmer4 · Answer

right, that's an essential point!

whpalmer4 · Answer

You get two solutions, but only one of them will make sense.