Step 1

There is total \(\displaystyle{\left({20}+{13}+{10}+{17}+{15}+{10}+{10}+{5}\right)}\%={100}\%\) students

Among them \(\displaystyle{\left({15}+{10}+{10}+{5}\right)}\%={40}\%\) is female.

So the probability of female student \(\displaystyle={\frac{{{40}\%}}{{{100}\%}}}={\frac{{{2}}}{{{5}}}}\)

Step 2

There are \(\displaystyle{\left({10}+{10}\right)}\%={20}\%\) juniors.

So the probability of junior \(\displaystyle={\frac{{{20}\%}}{{{100}\%}}}={\frac{{{1}}}{{{5}}}}\)

Step 3

c) \(\displaystyle{\left({10}+{10}\right)}\%={20}\%\) students are junior. Among them 10% is female.

So the required probability \(\displaystyle={\frac{{{10}\%}}{{{20}\%}}}={\frac{{{1}}}{{{2}}}}\)

Answer(a): \(\displaystyle{\frac{{{2}}}{{{5}}}}\)

Answer (b): \(\displaystyle{\frac{{{1}}}{{{5}}}}\)

Answer (c): \(\displaystyle{\frac{{{1}}}{{{2}}}}\)

There is total \(\displaystyle{\left({20}+{13}+{10}+{17}+{15}+{10}+{10}+{5}\right)}\%={100}\%\) students

Among them \(\displaystyle{\left({15}+{10}+{10}+{5}\right)}\%={40}\%\) is female.

So the probability of female student \(\displaystyle={\frac{{{40}\%}}{{{100}\%}}}={\frac{{{2}}}{{{5}}}}\)

Step 2

There are \(\displaystyle{\left({10}+{10}\right)}\%={20}\%\) juniors.

So the probability of junior \(\displaystyle={\frac{{{20}\%}}{{{100}\%}}}={\frac{{{1}}}{{{5}}}}\)

Step 3

c) \(\displaystyle{\left({10}+{10}\right)}\%={20}\%\) students are junior. Among them 10% is female.

So the required probability \(\displaystyle={\frac{{{10}\%}}{{{20}\%}}}={\frac{{{1}}}{{{2}}}}\)

Answer(a): \(\displaystyle{\frac{{{2}}}{{{5}}}}\)

Answer (b): \(\displaystyle{\frac{{{1}}}{{{5}}}}\)

Answer (c): \(\displaystyle{\frac{{{1}}}{{{2}}}}\)