Question 313161
Rate X time = distance

rt=d

Start by noticing which of the three elements are the same. In this problem the two cars are going different speeds and travelling different distances but they are both travelling for the same amount of time. So rearrange the formula:

{{{rt = d}}}
divide both sides by r: {{{(rt)/r = d/r}}}
 
the new formula is {{{t = d/r}}}

Now lets work the problem:

{{{(distance of first car)/(rate of first car) = (distance of second car)/(rate of second car)}}}

{{{14/x = 17.2/(x+8)}}}

Now cross multiply: {{{14(x+8)=17.2x}}}

Distribute: {{{14x + 112 = 17.2x}}}

Subtract 14x from both sides: {{{112 = 17.2x-14x}}}

{{{112 = 3.2x}}}

divide by 3.2 {{{112/3.2 =3.2x/3.2}}}

{{{35 = x}}}