The only way you can earn 0.1 btc per week has two options.
1. You will have a freelance job and receive your payment in bitcoin.
2. You will be a good trader and make profit from altcoin trading.
The rest is hard.
no they have many ways to earn 0.1 bitcoin a week like bounty campaign gives high payout but you need fee months before you get the payout. But if you have difference ways of earning like investing in ICO,investing in different altcoins, and Joining campaugn like bounty , and social campaign and signature campaign possible to earn 0.1 bitcoin a week and depends to your effort your payout.
Agreed, participation into different earning chances will increase the possibility of earning 0.1 btc per week. This too is a major attraction of people towards bitcoin. If they have the good skillsand time to spend on, surely 0.1btc is not at a big deal to be earned.