Answer:
k = - 
Step-by-step explanation:
Given that x varies directly with y then the equation relating them is
x = ky ← k is the constant of variation
To find k use the condition x = - 3 when y = 12
- 3 = 12k ( divide both sides by 12 )
= k , that is
k = - 
Answer is 0.2
To fnid the decimal, dovide the percentage by 100. 20/100 is 0.2.
I hope youre still around to read this
Answer:
2 molecule of hydrogen+oxygen=water