Answer:
Step-by-step explanation:
If two variables are directly proportional, it means that an increase in the value of one variable would cause a corresponding increase in the other variable. Also, a decrease in the value of one variable would cause a corresponding decrease in the other variable.
Given that Y varies directly with X, and Y = 15 and X = 5, if we introduce a constant of proportionality, k, the expression becomes
15 = 5k
k = 15/5
k = 3
The equation would be
Y = 3X
Therefore, when X = 9, the value of Y would be
Y = 3 × 9
Y = 27
