Dora drove east at a constant rate of 75 kph. one hour later, tim started driving on the same road at a constant rate of 90 kph. for how long was tim driving, before he caught up to dora?
i have tried to use a table
i set it up like this
name|d(mi)|r(kph)|t(hr.)|
dora | d |75 |t |
tim |d |90 |t+1 |
and then i went and i tried to put it into an equation
75t=90(t+2)
75t=90t+180
-90t -90t
-15t=180

-15 -15
t=-12
but it is not an answer on my multiple choice and it wouldn't be a negative 12 hours