y varies directly as x, and y=20 when x=5
y = 4x
When two variables vary directly, it means that they are related by a constant ratio. In this case, we can say that y varies directly as x. Mathematically, this can be represented as:
y = kx
where k is the constant of variation.
To find the value of k, we can use the given information that y = 20 when x = 5. Substituting these values into the equation, we get:
20 = k(5)
Now we can solve for k by dividing both sides of the equation by 5:
k = 20/5 = 4
So the constant of variation in this case is 4. Therefore, the equation that represents the direct variation between x and y is:
y = 4x