SOLUTION: A car traveling at a rate of 30 km/h left Gander. A second car left Gander 1 hour later. At what rate must the second car travel to catch up with the first in 3 hours?

Algebra ->  Real-numbers -> SOLUTION: A car traveling at a rate of 30 km/h left Gander. A second car left Gander 1 hour later. At what rate must the second car travel to catch up with the first in 3 hours?      Log On


   

Question 280061: A car traveling at a rate of 30 km/h left Gander. A second car left Gander 1 hour later. At what rate
must the second car travel to catch up with the first in 3 hours?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Start a stopwatch when the 2nd car leaves Gander
When I start the stopwatch, the 1st car has a
30%2A1+=+30 mile head start
When I stop the stopwatch, they both will have
driven for the same time, which is 3 hrs
1st car:
d%5B1%5D+=+30%2A3
d%5B1%5D+=+90 mi
2nd car:
d%5B2%5D+=+d%5B1%5D+%2B+30
d%5B2%5D+=+90+%2B+30
d%5B2%5D+=+120 mi
and
d%5B2%5D+=+r%5B2%5D%2A3
120+=+r%5B2%5D%2A3
r%5B2%5D+=+40
The 2nd car must drive 40 mi/hr to catch the 1st car