SOLUTION: Ellen and Kate raced on their bicycles to the library after school. They both left school at 3 pm and bicycled on the same path. Ellen rode at a speed of 12mph and Kate rode at 9

Algebra ->  Equations -> SOLUTION: Ellen and Kate raced on their bicycles to the library after school. They both left school at 3 pm and bicycled on the same path. Ellen rode at a speed of 12mph and Kate rode at 9      Log On


   

Question 1042508: Ellen and Kate raced on their bicycles to the library after school. They both left school at 3 pm and bicycled on the same path. Ellen rode at a speed of 12mph and Kate rode at 9mph. Ellen got to the library 15 min before Kate. What time did Ellen get to the library?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Start with time quantities, and deal with time points later. Identify knowns and unknowns. 

                RATE       TIME        DISTANCE
Ellen           12         t-1/4         d
Kate             9          t            d

Basic travel rates rule, RT=D
12%28t-1%2F4%29=9t