Three balls are drawn at random from a bag containing 5 blue and 4 yellow balls. Let the random variables X and Y respectively denote the number of…

Three balls are drawn at random from a bag containing $\displaystyle 5$ blue and $\displaystyle 4$ yellow balls. Let the random variables $\displaystyle X$ and $\displaystyle Y$ respectively denote the number of blue and yellow balls. If $\displaystyle \bar{X}$ and $\displaystyle \bar{Y}$ are the means of $\displaystyle X$ and $\displaystyle Y$ respectively, then $\displaystyle 7 \bar{X}+4 \bar{Y}$ is equal to $\displaystyle \_\_\_\_$.