Answer:
She can swin 3.6 km in 1 hour using freestyle.
Step-by-step explanation:
If she can swin 0.3 kilometers in 10 minutes or 1/6 hours using backstroke, then her speed on that style is:
[tex]v_{backstroke} = \frac{0.3}{\frac{1}{6}} = 0.3*6 = 1.8 \text{ } \frac{\text{km}}{\text{h}}[/tex]
If she can swim twice the distance in the same time for freestyle, then her speed on that is twice the one in backstroke. Therefore, her speed on freestyle is:
[tex]v_{freestyle} = 2*v_{backstroke} = 2*1.8 = 3.6 \text{ } \frac{\text{km}}{\text{h}}[/tex]
Since her speed in freestyle is 3.6 km per hour, this means that she can swim a total of 3.6 km in one hour.