Answer:
12 km
Step-by-step explanation:
Let
x km/h = speed of the canoe on the lake
y km/h = speed of the current
<u>With the current:</u>
Speed = x + y km/h
Distance = 30 km
Time = 3 hours 20 minutes =
hours
Thus,

<u>Against the current:</u>
Speed = x - y km/h
Distance = 28 km
Time = 4 hours
Thus,

Add these two equations:

<u>On the lake:</u>
Time = 1.5 hours
Speed = 8 km/h
Distance 
Answer:
C
Step-by-step explanation:
b is an <span> irrational number between 9 and 10</span>