Answer:
9 mph
Step-by-step explanation:
-let x be the speed of current and t be time. The speed equation for both directions can then be represented as:

#Since t is equal in both, we can do away with t.
#We the divide the downstream equation by the upstream equation as:

Hence, the boat's speed in still water is 9 mph
Number 2 is 84.13
number 4 is 56
Answer:
x=0 and y=3
Step-by-step explanation:
If x=0, then we can just plug that value into the other equation and solve for y:
x+4y=12
0+4y=12
4y=12
y=3
Therefore, the solution to the system of equations is x=0 and y=3