Roger Waters can scrape up just enough money to rent a canoe for 1 hour and 30 minutes. If he paddles out on a lake at 4 kph and returns at 2 kph, how far will he have paddled the canoe? Show work and table.

Question

dumbcow · Answer

im guessing we are assuming he is constantly paddling. 
d = r*t
however far out he went, he has to paddle the same distance to get back to shore
4t1 = 2t2  --> t2 = 2t1
this means it takes him twice as long to get back
t1 + t2 = 1.5  
by substitution
t1 + 2t1 = 1.5
3t1 = 1.5

t1 = 0.5
t2 = 1

d = 4*0.5 = 2*1 = 2
he paddled 2 km out and 2 km back for total of 4 km