Answer:
35
Step-by-step explanation:
If two things are directly proportional it means that their ratio is costant:
K (proportionality costant) : y/x
we know that when x=5 y=12
so:
K=5/12 (2.4)
we know that when x has a certain value, y=84
so:
2.4 = 84/x
we find the x to be 35
