Thank you chenlaoshi and zeit for both of your help. Thanks!

https://postimg.cc/Zv5tJHBR

The answer is 2 but i think it should be for 4 because i dont think it can totally remove all tiredness. TIA!

Thanks a lot . Appreciate you help sky minecrafter

https://postimg.cc/dZqHYfyk

Can someone explain why Q8's answer is 2. I think the answer is wrong. TIA