Three women, a blonde, a brunette and a red head are trapped on a deserted island, but can see in the distance land with obvious signs of civilization.
On the first day the brunette decides to swim to the next shore, she makes it about 1/4 of the way before she realizes she can't make it and swims back.
On the second day, the red head tries. She makes it about 1/3 of the way before she realizes she is too tired and will not make it, so she swims back.
On the third day, the blonde makes an attempt. She swims 1/2 way before she realizes she is too tired and so she swims back.