Question

Someone please help me with this

Answer 1

Answer:

$a.\ D=\dfrac{1}{5}t$

b. 20 seconds

Step-by-step explanation:

Let $D$ be the distance in miles and

$t$ be the time in seconds and

$s$ be the speed in miles/sec

Formula for Distance is given as:

$Distance = Speed \times Time\\OR\\D=st$

Given that:

Distance = 2 miles and

Time = 10 seconds

Putting the values in formula:

$2=s\times 10\\\Rightarrow s =\dfrac{1}{5} \ miles/sec$

Answer a:

Putting the value of $s$ back in the formula to find the direct variation equation for the relationship between time and distance:

$D=\dfrac{1}{5}t$

Answer b:

Using the above formula and putting $D=4\ miles$:

$4=\dfrac{1}{5}t\\\Rightarrow t =\bold{20\ seconds}$