Thanks!
The sender uses Bitcoins from different addresses. Compare it to paying in cash: you give a $20, a $10 and a $1 bill.
One transaction can pay to more than one address. In this case, there are 2 outputs, so it's likely one of them is a change address owned by the sender. In dollar terms: think of it as getting a nickel back.
Didn't understand why this is the case. If the sender pays from different addresses, should the system not make each into a seperate transaction? What is the cut-off for deciding which sends are consolidated into one transaction?