SOLUTION: Richard used his kayak and rows upstream at the rate of 3 kph and rows back downstream at the rate of 21 kph. If the complete trip requires 30 minutes. Find the total distance Rich

Question 590248: Richard used his kayak and rows upstream at the rate of 3 kph and rows back downstream at the rate of 21 kph. If the complete trip requires 30 minutes. Find the total distance Richard rowed.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Richard used his kayak and rows upstream at the rate of 3 kph and rows back downstream at the rate of 21 kph. If the complete trip requires 30 minutes. Find the total distance Richard rowed.
:
Let d = one-way distance rowed
then
2d = total distance
:
Change 30 min to .5 hrs
:
Write a time equation; time = dist/speed
+ = .5
multiply by 21
21* + 21* = 21*.5
cancel the denominators
7d + d = 10.5
8d = 10.5
d =
d = 1.3125 km one way
then
2 * 1.3125 = 2.625 km total distance
;
:
See if this checks out find the time each way
1.3125/3 = .4375 hrs
1.3125/21= .0625 hrs
--------------------
total time;.5 hrs; confirms our solution of 2.625 km total
RELATED QUESTIONS
A boat travels at the rate of 8 kph in still water. If it can travel a given distance... (answered by vleith)

a motorboat can travel 15 kph downstream and 9 kph upstream on a certain river. Find the... (answered by Alan3354)

a man can row 20 km downstream in the time it takes him to row 8 km upstream. he rows... (answered by lwsshak3)

A man rows downstream at the rate of 5 mph and upstream at the rate of 2mph. How far... (answered by stanbon)

A boy rows 6 miles downstream in 64 minutes. He rows back at the same rate in 180... (answered by stanbon)

A student rows at a constant speed (relative to the water) downstream in the Nambucca... (answered by ikleyn)

a man travels in a motor speed bangka at the rate of 15 kph from his barrio to the city... (answered by lwsshak3)

A man takes 5 hours and 20 minutes to row 6 miles up a river and back. If he can row 3... (answered by ikleyn)

a man travels in a motorized boat at the rate of 15 kph from his barrio to the city and... (answered by ewatrrr)