Question

Please someone can check out if my answer are correct and help me with # 18, 20, 21. Thanks

Answer 1

i just know the answer for 21st
ratio of forks to knifes is 8:10 
no. of forks is 16
⇒8/10 = 16/x (if x = to the no. of knifes)
⇒x=16*10/8
⇒x=2*10
⇒x=20.
∴ there are 20 knifes

Answer 2

Rest are correct , For remaining two See attachment :)