Answer:
The voyage of the James Caird was a journey of 1,300 kilometers (800 mi) from Elephant Island in the South Shetland Islands through the Southern Ocean to South Georgia, undertaken by Sir Ernest Shackleton and five companions to obtain rescue for the main body of the stranded Imperial Trans-Antarctic Expedition of 1914
So you subtract the fractal amounts from the whole with all of his customer being 1 and adding all the fractions 1-(1/8+2/5+3/10)
1-(1/8+4/10+3/10)
1-(1/8+7/10)
1-(5/40+28/40
1-(33/40)
1=40/40
40/40-33/40
7/40 of his customers chose a natural finish