SOLUTION: Bob can row 12 mph in still water. The total time to travel downstream and return upstream to the starting point is 2 hours and 40 minutes. If the total distance downstream and bac

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Bob can row 12 mph in still water. The total time to travel downstream and return upstream to the starting point is 2 hours and 40 minutes. If the total distance downstream and bac      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1143883: Bob can row 12 mph in still water. The total time to travel downstream and return upstream to the starting point is 2 hours and 40 minutes. If the total distance downstream and back is 30 miles, determine the speed of the river (current speed).
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
WAY            SPEED         TIME             DISTANCE

DOWNSTR         12+c                            15

BACKUP          12-c                            15

TOTAL                         2%262%2F3            30

Simplify and solve for c:
15%2F%2812%2Bc%29%2B15%2F%2812-c%29=2%262%2F3
.
.
.
c=3