Metro train increase

In the metro, trains run in one direction at the same speed and the same intervals. Yesterday, there were 24 trains throughout the day. More trains will run today, as the time interval between trains will be shorter by 20%. How many more trains will there be in the subway today?

Final Answer:

x =  6

Step-by-step explanation:

$$\begin{gathered} a=24 \\ r=100\%-20\%=1-\frac{20}{100}=0.8 \\ {T}_1=1/a=1/24=\frac{1}{24}\doteq 0.0417 \\ {T}_2=r\cdot T_1=0.8\cdot 0.0417=\frac{1}{30}\doteq 0.0333 \\ b=1/T_2=1/0.0333=30 \\ x=b-a=30-24=6 \end{gathered}$$

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