A fire truck is called to a scene. Three minutes later, a second truck is called. The first truck averages only 30 mi/h, but the second averages 60 mi/h. The trucks travel a total of 12 miles and arrive at the same time. How long from the first call did the trucks take to arrive? How far did each travel?

Question

A fire truck is called to a scene.  Three minutes later, a second truck is called.  The first truck averages only 30 mi/h, but the second averages 60 mi/h. The trucks travel a total of 12 miles and arrive at the same time.  How long from the first call did the trucks take to arrive? How far did each travel?

anonymous · Answer

first truck traveled 3 miles and second traveled 9 miles
First truck took 6 mins and second truck 12 mins from the first call

anonymous · Answer

just solve the two equations 
x+y=12
60*(y/60-x/30)=3

anonymous · Answer

you got caroline??

ybarrap · Answer

$V_1$ is the speed of the 1st truck
$V_2$ is the speed of the 1st truck
$t_1$ is the time of travel for the 1st truck
$t_2$ is the time of travel for the 2nd truck
$t_2=t_1+3$
The distance the 1st truck travels is $V_1\times t_1$
The distance the 2nd truck travels is $V_2\times t_2$
The total distance they travel is  $V_1\times t_1+V_2\times t_2=12$
$$
V_1 t_1+V_2 t_2=12\
V_1t_1+V_2 (t_1+3)=12\
V_1t_1+V_2 t_1=12-3V_2\
\implies t_1(V_1+V_2)=12 -3V_2\
t_1={{12 -3V_2} \over V_1+V_2}
$$
You now have $t_1$, from which you can get $t_2$ and the distances traveled by each truck.