Suppose Kyoko is currently using combination D$,$ producing one picture frame per day. Her opportunity cost of producing a second picture frame per day is per day.

Now, suppose Kyoko is currently using combination C$,$ producing two picture frames per day. Her opportunity cost of producing a third picture frame per day is $\_$ per day.

From the previous analysis, you can determine that as Kyoko increases her production of picture frames, her opportunity cost of producing one more picture frame

Suppose Kyoko buys a new tool that enables her to produce twice as many picture frames per hour as before, but it doesn't affect her ability to produce cutting boards. Use the green points $($triangle symbol$)$ to plot her new PPF on the previous graph.

Because she can now make more picture frames per hour, Kyoko's opportunity cost of producing cutting boards is it was previously.