Answer:
11. This is an input problem. The hours needed to produce one unit represent the input required to produce each unit of ukuleles and surfboards.
12. Jack's opportunity cost of producing 1 ukulele is 3 surfboards. This means that if Jack decides to produce 1 ukulele, he foregoes the opportunity to produce 3 surfboards.
13. Jack's opportunity cost of producing 1 surfboard is 0.3 ukuleles. This means that if Jack decides to produce 1 surfboard, he foregoes the opportunity to produce 0.3 ukuleles.
14. Jill's opportunity cost of producing 1 ukulele is 5 surfboards. This means that if Jill decides to produce 1 ukulele, she foregoes the opportunity to produce 5 surfboards.
15. Jill's opportunity cost of producing 1 surfboard is 0.2 ukuleles. This means that if Jill decides to produce 1 surfboard, she foregoes the opportunity to produce 0.2 ukuleles.
16. Jill has the absolute advantage in producing ukuleles because she can produce 1 ukulele in 25 hours, while Jack requires 12 hours to produce 1 ukulele.
17. Jack has the absolute advantage in producing surfboards because he can produce 1 surfboard in 4 hours, while Jill requires 5 hours to produce 1 surfboard.
18. Jill has the comparative advantage in producing ukuleles because her opportunity cost of producing 1 ukulele (5 surfboards) is lower than Jack's opportunity cost of producing 1 ukulele (3 surfboards).
19. Jack has the comparative advantage in producing surfboards because his opportunity cost of producing 1 surfboard (0.3 ukuleles) is lower than Jill's opportunity cost of producing 1 surfboard (0.2 ukuleles).