SOLUTION: Wayne travels from A to B which is 50km. He then travels from B to C which is 40km. He takes 40 minutes to go from A to B. How fast does he have to travel from B to C such that the

Algebra ->  Length-and-distance -> SOLUTION: Wayne travels from A to B which is 50km. He then travels from B to C which is 40km. He takes 40 minutes to go from A to B. How fast does he have to travel from B to C such that the      Log On


   

Question 1041090: Wayne travels from A to B which is 50km. He then travels from B to C which is 40km. He takes 40 minutes to go from A to B. How fast does he have to travel from B to C such that the entire journey takes 1 hour and 10 minutes?
Please explain thoroughly thank you?,
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
Put everything into a table of data.
RT=D is the travel rates rule relating R rate, T time, and D distance. 
              RATE         TIME       DISTANCE
A to B         s            2%2F3           50
B to C         r            t             40
TOTAL                      1%261%2F6

Some cell values are not yet known but are filled using variables as shown in the table.
Time is in HOURS.

The time going from B to C is simple to find.
1%261%2F6-2%2F3=t
7%2F6-4%2F6=t
3%2F6=t
highlight_green%28t=1%2F2%29

The question essentially asks for solution of r. The number for speed or rate s is not even needed.

r%2At=40
r%2A%281%2F2%29=40
r=40%2A2
highlight%28highlight%28r=80%29%29