Final answer:
Lenny's speed while paddling upstream is 2 km/h, his speed while paddling downstream is 6 km/h, and the speed of the current is 2 km/h.
Step-by-step explanation:
In order to calculate the speed of the current, we need to determine Lenny's speed while paddling upstream and downstream.
a) To calculate Lenny's speed while paddling upstream, we can subtract the speed of the current from his speed in still water. Lenny's speed while paddling upstream is 4 km/h - x km/h, where x is the speed of the current.
b) To calculate Lenny's speed while paddling downstream, we can add the speed of the current to his speed in still water. Lenny's speed while paddling downstream is 4 km/h + x km/h.
c) We can create a chart to organize the information:
DirectionSpeedTimeDistanceUpstream4 km/h - x km/ht8 kmDownstream4 km/h + x km/h5 - t8 km
d) Given that the total trip takes 5 hours, we can set up the following equation: t + (5 - t) = 5. Solving for t, we find that t = 2.5 hours. Plugging this value back into the chart, we can determine Lenny's speed while paddling upstream and downstream:
a) Lenny's speed while paddling upstream = 4 km/h - x km/h = 4 km/h - x km/h = 2 km/h. b) Lenny's speed while paddling downstream = 4 km/h + x km/h = 4 km/h + x km/h = 6 km/h. c) The completed chart looks like this:
DirectionSpeedTimeDistanceUpstream2 km/h2.5 hours8 kmDownstream6 km/h2.5 hours8 km
d) Using the chart, we can see that Lenny's speed while paddling upstream is 2 km/h and his speed while paddling downstream is 6 km/h. To calculate the speed of the current, we subtract Lenny's speed while paddling upstream from his speed while paddling downstream: c = (6 km/h - 2 km/h) / 2 = 4 km/h / 2 = 2 km/h.