Calculate 7451

The car will cover a certain distance in 3 hours and 20 minutes. If he increases his speed by 10 km/h, he will cover this distance in 2.5 hours. Calculate this distance.

Correct answer:

s =  100 km

Step-by-step explanation:

$$\begin{gathered} t_1=3:20=3hr20min=3+\frac{20}{60}=3.3333hr\doteq 3.3333 \\ {t}_2=2.5\text{h} \\ s=v\cdot t_1 \\ s=(v+10)\cdot t_2 \\ v\cdot t_1=(v+10)\cdot t_2 \\ v\cdot 3.3333333333333=(v+10)\cdot 2.5 \\ 0.833333v=25 \\ v=\frac{25}{0.83333333}=30 \\ v=30 \\ s=v\cdot t_1=30\cdot 3.3333=100\text{km} \end{gathered}$$

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