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A bicyclist traveled with a speed of 12 km/h from a camping ground to a station, located 60 km away. Write a formula expressing the dependence of the variable s on t, where s is the distance between the bicyclist and the station in km, t - the duration (time) of his travel in hours. Using the formula, find s for t=3.5 AND t for s=30 (AND = separate)

Respuesta :

calculista

Let

s-------> is the distance in Kilometer

V-----> the speed of the bicyclist in Km/h

t------> is the time in hours

we know that

[tex]V=s/t[/tex]

in this problem we have

[tex]V=12\frac{Km}{h}[/tex]

Part a) Find s for [tex]t=3.5\ h[/tex]

we know that

[tex]V=s/t[/tex]

solve for s

[tex]s=Vt[/tex]

substitute the values

[tex]s=12*3.5=42\ Km[/tex]

therefore

the answer Part a) is

[tex]42\ Km[/tex]

Part b) Find t for [tex]s=30\ Km[/tex]

we know that

[tex]V=s/t[/tex]

solve for t

[tex]t=s/V[/tex]

substitute the values

[tex]t=30/12=2.5\ h[/tex]

therefore

the answer Part b) is

[tex]2.5\ h[/tex]

Answer:

Part A) 18 km           Part B) 2.5 hours

Step-by-step explanation:

Part A:

Formula: s = 60 - 12t

Substitute numbers:

s = 60 - 12(3.5) = 60 - 42 = 18 km

Part B:

Formula: s = 60 - 12t

Substitute numbers:

30 = 60 - 12t

30 - 60 = -12t

-30 = -12t

t = 2.5 hours