\[\boxed{\mathbf{100.}}\]
\[2x + 3y + 4y + 5x =\]
\[= 7x + 7y = 7(x + y).\]
\[Сумма\ частот\ равна\ 1:\]
\[x + x + y + y = 1\]
\[2x + 2y = 1\]
\[(x + y) = \frac{1}{2}.\]
\[Среднее\ значение:\]
\[7(x + y) = 1 \cdot \frac{1}{2} = 3,5.\]
\[Ответ:3,5.\]