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2. A car travels 50 km/h for 3000 meters to its destination. How long did car travel to reach its destination?

Sagot :

Answer:

0.06 h or 3.6 minutes

Explanation:

First convert 3000 meters to kilometers, because speed is also in that unit (km/h)

distance: [tex]s = 3000 m = 3 km[/tex]

speed: [tex]v = 50 km/h[/tex]

time: [tex]t = \frac{s}{v}[/tex]

Substitute in and solve:

[tex]t = \frac{3 km}{50 \frac{km}{h} }[/tex]

[tex]t = \frac{3}{50} h[/tex]

[tex]t = 0.06 h[/tex] or [tex]3.6 min[/tex] (0.06 h * 60 min/h)

Suppose we know the formula of speed:

[tex]\displaystyle{v=\dfrac{s}{t}}[/tex]

Where v = speed, s = distance and t = time.

We can solve the equation for time by first multiplying both sides by t:

[tex]\displaystyle{v\cdot t = \dfrac{s}{t} \cdot t}\\\\\displaystyle{vt = s}[/tex]

This results in distance equation but that’s not what we want for now. Divide both sides by v:

[tex]\displaystyle{\dfrac{vt}{v}=\dfrac{s}{v}}\\\\\displaystyle{t=\dfrac{s}{v}}[/tex]

Finally, we have the time equation as shown above.

From the question, we know that v (speed) = 50 km/h and s (distance) = 3000 meters. However, since speed and distance both have different unit, we will have to change from meters to kilometers.

We know that a kilometer equals 1000 meters. Therefore, 3000 meters equal to 3 kilometers. Therefore, our new value of distance (s) is 3 kilometers.

Apply the time equation by substituting v = 50 and s = 3:

[tex]\displaystyle{t=\dfrac{3 \ \, \sf{km}}{50 \ \, \sf{km/h}}}\\\\ \displaystyle{t=\dfrac{3\cdot 2 \ \, \sf{km}}{50\cdot 2 \ \, \sf{km/h}}}\\\\\displaystyle{t=\dfrac{6 \ \, \sf{km}}{100 \ \, \sf{km/h}}}\\\\\displaystyle{t=0.06 \ \, \sf{h}}[/tex]

Generally, time must be in second unit. Therefore, we’ll convert from hour to second.

We know that an hour equals to 60 minutes and a minute equals to 60 seconds. Therefore, an hour equals to 60 x 60 seconds = 3600 seconds.

Thus, 0.06 hour will equal to 3600 x 0.06 which equals to 216 seconds. Therefore, it’ll take 216 seconds to reach the destination.