Answer:
1.5 mph
Step-by-step explanation:
The speed in the still water = 6.5 mph.
The speed of the current = x mph.
1. Two friends traveled with current for 3 hours. The speed with the current is 6.5 + x mph, so they traveled [tex]3(x+6.5)[/tex] miles.
2. Two friends traveled against the current for 4 hours and 48 minutes that is [tex]4\dfrac{4}{5}=4.8[/tex] hours. The speed against the current is 6.5 - x mph, so they traveled [tex]4.8(6.5-x)[/tex] miles.
They traveled the same distance with the current and against the current, hence,
[tex]3(x+6.5)=4.8(6.5-x)[/tex]
Solve this equation:
[tex]3x+19.5=31.2-4.8x\\ \\3x+4.8x=31.2-19.5\\ \\7.8x=11.7\\ \\x=1.5\ mph[/tex]
