You can solve this problem by applying the proccedure below:
You have:
a) 18/21=2/3 18x3/21x2 36≠42 (2/3 is not proportinal to 18/21).
b)18/21=30/35 18x35/21x30 630=630 (30/35 is proportional to 18/21)
c)18/21=36/48 18x48/21x36 864≠756 (36/48<span> is</span><span> not proportinal to 18/21) </span> d)18/21=1/3 18x3/21x1 54≠21 (<span> 1/3 is</span><span> not proportinal to 18/21) </span> Therefore, you can conclude that the correct option is: B.30/35
