Dana can run at a rate of speed four times faster than she can walk, but she can skip at a rate of speed that is half as fast as she can run. If she can skip at 3 miles per hour, how many miles can she travel in six hours if she spends one-third of the time running and two-thirds of the time walking?
If Dana can skip at half the speed she can run, then she can run at 3*2=<<3*2=6>>6 miles per hour.
And since she can run at a speed that is 4 times faster than she can walk, this means she can walk at 6/4=1.5 miles per hour.
If two-thirds of the time is spent walking, then she walks for 6*(2/3)=<<6*(2/3)=4>>4 hours.
If one-third of the time is spent running, then she runs for 6-4=<<6-4=2>>2 hours.
Thus, she runs for 2 hours at 6 miles per hour, or 2*6=<<2*6=12>>12 miles.
She walks for 4 hours at 1.5 miles per hour, or 4*1.5=<<4*1.5=6>>6 miles.
Thus, altogether, she travels 12+6=<<12+6=18>>18 miles.
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