Safe percentage= %30-40
a-If things go bad you probably lose half of your money. (Price goes to 200$)
b-If things go worse than bad you lose it all.
c-If things go well you probably profit around %20 in a year.
d-If things go better than well, you will make +%100 profit.
a and c got more chances to happen than the other options. and "c" probably will happen rather than "a". (in a year)
That's why we have to make some broad investment strategy on how we will handle all our funds in exchanges. People think that if they will just hold 1 btc it will take them to profits without doing nothing. There are lots of ways to handle our investment in bitcoin and also there are ways to minimize the loss.