Given $X$ and $Y$ and a percent, how do I calculate the quantity that is that percent between them? Here is a really dumb question, but I cannot find answers on Google for some reason or other.  All the answers seem to be buried under mounds of percent difference formulas (which is not what I am asking).
I am trying to generate a value between two variables based on a percentage.
$$\begin{align*}
0\% &= X \qquad \text{(the minimum value)}\\\\
50\% &= \frac{X + Y}{2}\\\\
100\% &= Y\qquad \text{(the maximum value)}
\end{align*}$$
What would the formula be?

$$X+(\text{percent here})\cdot(Y-X)$$
So for example,
$X+(25\%)\cdot(Y-X)$ is $25$ percent of the way to $Y$, from $X$.
