Cylindrical container 1: Diameter D1 = 15 cm, Depth h1 = 20 cm

For container 1: $r_1 = \frac{D_1}{2} = \frac{15}{2} = 7.5$ cm
For jar 2: $r_2 = \frac{D_2}{2} = \frac{10}{2} = 5$ cm

The volume of a cylinder is given by $V = \pi r^2 h$.

When the water is poured into jar 2, its volume remains the same, so $V_2 = V_1$.
Let $h_2$ be the depth of water in jar 2.

Divide both sides by $25 \pi$:

The depth of the water in the jar is $\boxed{\text{45 cm}}$.

13 c)
Given:

• Cylindrical tank: Diameter $D = 5.0$ m, Volume of water $V = 110 000$ dm$^3$

Let's convert everything to meters.
Radius $r = \frac{D}{2} = \frac{5.0 \text{ m}}{2} = 2.5$ m
Volume $V = 110 000$ dm$^3$. Since $1 \text{ m} = 10 \text{ dm}$, then $1 \text{ m}^3 = (10 \text{ dm})^3 = 1000 \text{ dm}^3$.

The volume of a cylinder is $V = \pi r^2 h$. We need to find $h$.
Using $\pi = \frac{22}{7}$:

The height of the water in the tank is $\boxed{\text{5.6 m}}$.