SOLUTION: If I am riding a bike at 18 mph and my friend is riding 3 miles ahead at 12 mph. How long before I catch up to him?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: If I am riding a bike at 18 mph and my friend is riding 3 miles ahead at 12 mph. How long before I catch up to him?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 994497: If I am riding a bike at 18 mph and my friend is riding 3 miles ahead at 12 mph. How long before I catch up to him?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = distance in miles you travel
until you catch friend
Let +t+ = time in hours it takes you
to catch friend
-----------------------
Friend's equation:
(1) +d+-+3+=+12t+
Your equation:
(2) +d+=+18t+
-----------------
Substitute (2) into (1)
(1) +18t+-+3+=+12t+
(1) +6t+=+3+
(1) +t+=+1%2F2+
---------------
You will catch friend in 1/2 hr
---------------
check:
(2) +d+=+18%2A%281%2F2%29+
(2) +d+=+9+
and
(1) +d+-+3+=+12%2A%281%2F2%29+
(1) +d+-+3+=+6+
(1) +d+=+9+
OK