Question

A train is traveling at a constant speed and goes 7.5 kilometers in 6 min How far does the train go in 1 min

Answer 1

As the speed is constant, we can use the rule of three to calculate how far itgoes in 1 min.

If it goes 7.5 km in 6 min:

$\begin{gathered} 6\min \longrightarrow7.5\operatorname{km} \\ 1\min \longrightarrow x=7.5\operatorname{km}\cdot\frac{1\min}{6\min}=\frac{7.5}{6}=1.25\operatorname{km} \end{gathered}$

NOTE: If we want to calculate how far it goes in 100 minutes, we apply the same rule:

$\begin{gathered} 6\min \longrightarrow7.5\operatorname{km} \\ 100\min \longrightarrow x=7.5\operatorname{km}\cdot\frac{100\min }{6\min }=\frac{750}{6}=125\operatorname{km} \end{gathered}$

Or we can just multiply 1.25 km/min, which is the speed, by 100 min, and get 125 km.

Answer: The train will travel 1.25 km in one minute.