71. On a horizontal desktop, there are three cylindrical containers (sufficiently high) named Jia, Yi, and Bing, with the ratio of their base radii being $1: 2: 1$. Two identical tubes connect the containers at a height of $5 \mathrm{~cm}$ (the bottom end of the tubes is $5 \mathrm{~cm}$ above the container bottom). Only Jia contains water, with a water level of $1 \mathrm{~cm}$, as shown in the figure. Now, water is added to Yi and Bing at the same rate. After half a minute, the water level in Yi rises by $\frac{5}{12} \mathrm{~cm}$. Then, after $\qquad$ minutes or $\qquad$ minutes or $\qquad$ minutes, the difference in water level height between Jia and Yi is $\frac{1}{2} \mathrm{~cm}$.
Answer: $\frac{3}{5} ; \frac{33}{20} ; \frac{171}{40}$