Find the variation constant and an equation of variation where y varies directly as x and y = 20 when x = 10

To find the variation constant and an equation of variation where y varies directly as x, we can use the formula for direct variation:

y = kx

where y is the dependent variable, x is the independent variable, and k is the variation constant.

We are given that y = 20 when x = 10. We can substitute these values into the equation to solve for k.

20 = k * 10

Divide both sides of the equation by 10 to isolate the variation constant:

k = 20 / 10

Simplifying the right side gives:

k = 2

So, the variation constant is 2.

Now that we have the variation constant, we can write the equation of variation:

y = 2x

This equation represents direct variation, where y varies directly with x, and the variation constant is 2.