Answer :
Answer:
[tex]a.\ D=\dfrac{1}{5}t[/tex]
b. 20 seconds
Step-by-step explanation:
Let [tex]D[/tex] be the distance in miles and
[tex]t[/tex] be the time in seconds and
[tex]s[/tex] be the speed in miles/sec
Formula for Distance is given as:
[tex]Distance = Speed \times Time\\OR\\D=st[/tex]
Given that:
Distance = 2 miles and
Time = 10 seconds
Putting the values in formula:
[tex]2=s\times 10\\\Rightarrow s =\dfrac{1}{5} \ miles/sec[/tex]
Answer a:
Putting the value of [tex]s[/tex] back in the formula to find the direct variation equation for the relationship between time and distance:
[tex]D=\dfrac{1}{5}t[/tex]
Answer b:
Using the above formula and putting [tex]D=4\ miles[/tex]:
[tex]4=\dfrac{1}{5}t\\\Rightarrow t =\bold{20\ seconds}[/tex]