$0.20 Because since one ribbon for one foot equals $0.10 (10 cents), you have two feet so you would have to multiply or add $0.10 and $0.10 by multiplying, you would have to multiply 10 two times which would give you 20. To add you would add 10 plus 10 and you would get yet again 30. After that you just put the form as cents which would be $0.20 :)