\[\boxed{\mathbf{292.}}\]
\[Всего\ гимнасток:\]
\[7 + 8 + 5 = 20.\]
\[\textbf{а)}\ Р = \frac{7}{20} = \frac{35}{100} = 0,35.\]
\[\textbf{б)}\ Р = \frac{8}{20} = \frac{40}{100} = 0,4.\]
\[\textbf{в)}\ Р = \frac{7 + 5}{20} = \frac{12}{20} = 0,6.\]
\[\textbf{г)}\ Р = \frac{7 + 8}{20} = \frac{15}{20} = \frac{75}{100} = 0,75.\]