Here are the solutions to the problems. Problem 1: Cylindrical and Rectangular Tank Step 1: Calculate the radius of the cylindrical tank. The diameter is $5.6 \text{ m}$, so the radius $r$ is half of the diameter. $$r = \frac{5.6 \text{ m}}{2} = 2.8 \text{ m}$$ Step 2: Calculate the volume of water in the cylindrical tank. The formula for the volume of a cylinder is $V = \pi r^2 h$. Given $h_c = 2.5 \text{ m}$. We will use $\pi = \frac{22}{7}$. $$V_c = \pi (2.8 \text{ m})^2 (2.5 \text{ m})$$ $$V_c = \frac{22}{7} \times (2.8 \text{ m}) \times (2.8 \text{ m}) \times (2.5 \text{ m})$$ $$V_c = 22 \times (0.4 \text{ m}) \times (2.8 \text{ m}) \times (2.5 \text{ m})$$ $$V_c = 8.8 \text{ m} \times 2.8 \text{ m} \times 2.5 \text{ m}$$ $$V_c = 24.64 \text{ m}^2 \times 2.5 \text{ m}$$ $$V_c = 61.6 \text{ m}^3$$ Step 3: Set up the equation for the volume of water in the rectangular tank. The volume of water transferred to the rectangular tank is the same as the volume in the cylindrical tank. The formula for the volume of a rectangular tank is $V = L \times W \times h$. Given $L = 5.5 \text{ m}$ and $W = 4 \text{ m}$. Let $h_r$ be the height of the water in the rectangular tank. $$V_r = (5.5 \text{ m}) \times (4 \text{ m}) \times h_r$$ $$V_r = 22 h_r \text{ m}^2$$ Step 4: Solve for the height of the water in the rectangular tank. Since $V_c = V_r$: $$61.6 \text{ m}^3 = 22 h_r \text{ m}^2$$ $$h_r = \frac{61.6 \text{ m}^3}{22 \text{ m}^2}$$ $$h_r = 2.8 \text{ m}$$ The height of the water in the rectangular tank was $\boxed{2.8 \text{ m}}$. Problem 2: Half Marathon Speed Step 1: Convert the distance from kilometers to meters. The race is $21 \text{ km}$ long. $$1 \text{ km} = 1000 \text{ m}$$ $$D = 21 \text{ km} \times \frac{1000 \text{ m}}{1 \text{ km}} = 21000 \text{ m}$$ Step 2: Convert the time from hours and minutes to seconds. Peter ran the race in $1 \text{ hour } 40 \text{ minutes}$. $$1 \text{ hour} = 60 \text{ minutes}$$ Total minutes = $60 \text{ minutes} + 40 \text{ minutes} = 100 \text{ minutes}$$ $$1 \text{ minute} = 60 \text{ seconds}$$ Total seconds = $100 \text{ minutes} \times \frac{60 \text{ seconds}}{1 \text{ minute}} = 6000 \text{ seconds}$$ Step 3: Calculate Peter's speed in meters per second. The formula for speed is $S = \frac{D}{T}$. $$S = \frac{21000 \text{ m}}{6000 \text{ s}}$$ $$S = \frac{21}{6} \text{ m/s}$$ $$S = 3.5 \text{ m/s}$$ Peter's speed was $\boxed{3.5 \text{ m/s}}$. That's 2 down. 3 left today — send the next one.