Answer :
A little mermaid can't swim 12 miles downstream in the same amount of time she can swim 8 miles upstream. The little mermaid speed's in still water is: 4/5 mile per hour.
The distance of the miles can be estimated by using the formula:
distance = speed rate × time
∴
[tex]\mathbf{time = \dfrac{distance}{ rate}}[/tex]
Let the current speed be = x
In the upstream direction;
- the rate = swim speed - the current speed
- = 4 - x
in the downstream direction;
- the rate = 4 + x
∴
[tex]\mathbf{t = \dfrac{8}{4 -x}= \dfrac{12}{4+x}}[/tex]
By cross multiply;
8 (4 + x) = 12 (4 - x)
32 + 8x = 48 - 12x
8x + 12x = 48 - 32
20x = 16
x = 16/20
x = 4/5 mile per hour
Therefore, we can conclude that the little mermaid speed's in still water is 4/5 miles per hour.
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