Pools & pace
Volume = length × width × depth; 1 m³ = 1,000 L. A sloped floor: use the average depth. Speed = distance ÷ time; pace = time per 100 m.
Pressure p = ρgh = 1,000 × 9.8 × depth (Pa). Currents add as vectors at right angles. Swim where a lifeguard is on duty, and wear a lifejacket in boats and open water.
One step
Area, volume and splits.Pool deck
A pool is 25 m by 15 m. What is its surface area and its perimeter?
Fill it
The pool is 1.8 m deep all over. What is its volume in m³ and in litres?
Splits
A swimmer’s 50 m splits are 34, 36, 37 and 35 seconds. What is the 200 m time in minutes and seconds? The average split?
Deep end
What is the water pressure 3 m down (on top of air pressure)?
Two or three steps
Sketch the pool or river first.Sloped floor
A 25 m by 10 m pool slopes evenly from 1 m deep to 3 m. What is its volume?
Diagonal
How long is the corner-to-corner diagonal of a 25 m by 15 m pool?
River current
A swimmer heads straight across a 36 m river at 0.9 m/s. The current flows at 1.2 m/s. Find the real speed, the time to cross, how far downstream they land and the angle off straight across.
Pace
An 800 m swim takes 14:40. What is the average speed in m/s, and the pace per 100 m?
Stroke rate
A swimmer takes 36 strokes a minute and travels 1.75 m per stroke. What is the speed in m/min and m/s?
Drowning data
Alberta had 44 water-related deaths in 2024. Using the 2020–24 pattern of 26% in lakes and 31% in rivers, about how many were in lakes? In rivers and lakes together?
Equations
A1–A2 (pp.17–18).Fill time
A pool holds 200,000 L and a hose adds 25,000 L an hour. Solve 200,000 + 25,000t = 700,000.
Pass or pay?
Drop-in costs $7 a visit. A pass is $50 plus $2.50 a visit. Solve 7v = 50 + 2.5v. From how many visits is the pass cheaper?
Platform
From a 7.2 m platform, h = 7.2 − 5t². When does a diver reach the water?
Deck border
A 12 m by 20 m pool gets a deck of even width x. The pool and deck cover 384 m². Solve (12 + 2x)(20 + 2x) = 384.
Your turn to be the lifeguard
- Pick a pool, lake or river you know.
- Write a question about its area, volume, a swimmer’s pace or a current.
- Solve it, then add one safety rule the numbers support.
My problem, and my worked answer:
Try every problem first, then check here. Wrong answers are useful: find the step where your work and the key split apart.
The key never prints with Print my work or Print blank. Open it to get its own Print the answer key button.
Answer key
Worked solutions. Drowning figures: Lifesaving Society Alberta snapshot (p.15). Swim with a lifeguard on duty.