Answer:
x = 49 mi/hr
y = 6 mi/hr
Explanation:
A motorboat travels 258mi in 6 hours going upstream. It travels 330mi going downstream in same amount of time. What's the rate of the boat in still water and what is the rate of the current.
Let
x = the speed of the boat in still water.
y = the speed of the stream
The speed upstream is x - y
The speed downstream is x + y
Distance = rate × time
258 = (x - y)6 (1)
330 = (x + y)6 (2)
From (1)
x - y = 43 (3)
From (2)
x + y = 55 (4)
x - y = 43 (3)
x + y = 55 (4)
Add the equations to eliminate y
x + x = 43 + 55
2x = 98
x = 98/2
x = 49 mi/hr
Substitute x = 49 into (4)
x + y = 55 (4)
49 + y = 55
y = 55 - 49
y = 6 mi/hr