^{_{20. B}}

^{_{21. A}}

^{_{22. A}}

^{_{23. D}}

^{_{24. B}}

^{_{25. B}}

^{_{26. A}}

^{_{27. B}}

^{_{28. A}}

^{_{29. A}}

^{_{30. A}}

^{_{31. B}}

^{_{32. D}}

^{_{11. A}}

^{_{12. A}}

^{_{13. B}}

^{_{14. A}}

^{_{15. C}}

^{_{16. B}}

^{_{17. C}}

^{_{18. C}}

^{_{19. D}}

^_driver

^_unpredicted

^{_{\(\dfrac{4}{5}\)dm3 = 800 cm3}}

+A = \(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+\(\dfrac{1}{3.4}\)+...+\(\dfrac{1}{49.50}\)

A = 1 - \(\dfrac{1}{2}\)+\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\)+\(\dfrac{1}{3}\)-\(\dfrac{1}{4}\)+...+\(\dfrac{1}{49}\)-\(\dfrac{1}{50}\)

A = 1 - \(\dfrac{1}{50}\)

A = \(\dfrac{50}{50}\) - \(\dfrac{1}{50}\)

A = \(\dfrac{49}{50}\)