This is a hard question. In a sense they're both very important. Without the giver Jonas wouldn't have received any memories. The Giver is essential to the story. So is Jonas though. Without him there would be no receiver and the memories wouldn't have been released to the community and the giver wouldn't have been able to pass down the memories.
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
