Sir/maam Please could you answer the following questions

Dear student,
6)
From the given data
6 full glasses = (3/5) of  jar.
1 full glass = (3/15)
 = (1/5).
so when 1 full glass was drunk the remaining part = $\frac{3}{5}- \frac{1}{5} = \frac{2}{5}$.
please post again our experts will assist you as soon as possible .
Regards