A brunette, a readhead and a blonde come across a wide river they need to pass...

Not being any bridge, they have to get past it by swimming.

First goes the brunette, she swims a quarter of the river, she gets tired and drowns.

Second is the readhead, she swims halfway the river, she gets tired and drowns.

And lastly goes the blonde. She swims three quarters of the river, gets tired and swims back at the shore where she started so she won't drown.

Poorly translated from romanian