All concepts combined
Primary 5 Volume study guide: the whole chapter, step by step
About this subtopic
This mixed practice stop brings together 6 topics from Primary 5 Volume: Building with unit cubes, The volume of a cuboid, On the isometric grid, The water level, Litres, ml and cm³, Pouring between containers. Nothing on the question says which topic it comes from, so choosing the method is part of the skill.
Practice questions with worked solutions
Question 1 is free to try. The other 2 open in the free trial, each with its full working.
Print this subtopic · included with a plan
2 more questions, each with its full working.Answers checked, progress kept, wrong ones come back in revision. No card needed.
Start the 7-day free trialQuestion 1 of 3 · Intermediate · free to tryA rectangular tank measures 45 cm long, 25 cm wide and 40 cm high. The tank…A rectangular tank measures…
A rectangular tank measures 45 cm long, 25 cm wide and 40 cm high. The tank is 2/5 full of water. Another 9000 cm³ of water is then poured into the tank. Find the depth of the water in the tank.
Show the working and the answer
Working
- volume of a cuboid = length × breadth × height
- capacity of the tank = 45 × 25 × 40 = 45000
- volume of water at first = 2/5 × 45000 = 18000
- volume of water now = 18000 + 9000 = 27000
- base area of the tank = 45 × 25 = 1125
- depth of the water = 27000 ÷ 1125 = 24 cm
Answer: 24 cm
For parents
How should my child set out P5 volume mixed practice questions?
These questions put water in rectangular tanks and ask for more than one thing about it.
What your child learns here
These questions put water in rectangular tanks and ask for more than one thing about it. A tank a fraction full gives a volume, then a top-up gives a new depth; water poured from one tank into another settles at the same depth in both; a tank filled to the brim needs its answer in litres. The work uses the Primary 5 outcomes on the volume of liquid in a rectangular tank and on litres and cm³, run forwards to a volume and backwards to a depth.
- The volume of water is the base area times the depth of the water, not the height of the tank.
- A tank 2/5 full holds 2/5 of its capacity, which is the water standing at 2/5 of its height.
- To find a depth, divide the volume of water by the base area of the tank.
- Water poured between tanks keeps its volume; only the base it stands on changes.
- 1000 cm³ is 1 litre, so divide a volume in cm³ by 1000 to give it in litres.
Does the answer make sense?
A depth can never be more than the height of its tank. When water is levelled between two tanks, the shared depth must be lower than the 18 cm Tank A started with and above zero, and 12 cm is; 12 cm on both bases, 1200 cm² and 600 cm², gives back the 21 600 cm³ that was there at the start.
How to practise these questions
All three questions are Intermediate. The first fills a tank 45 cm by 25 cm by 40 cm to 2/5 of its capacity, adds 9000 cm³ more, and asks for the new depth. The second pours water from Tank A into empty Tank B until the two depths match, so your child adds the two base areas and shares the water over both. The third finds how much water fills a tank from a depth of 14 cm to the brim and gives it in litres. Ask your child to write the base area of each tank on its own line before any volume, because every step uses it.
Questions parents ask
Is finding the depth of water a Primary 5 skill? The MOE syllabus lists the volume of liquid in a rectangular tank at Primary 5 and finding a height from a volume and a base area at Primary 6. These questions use the Primary 5 formula in both directions, so they also prepare your child for Primary 6.
Why give the answer in litres when the tank is in centimetres? Lengths in centimetres give a volume in cm³, and taps and tanks are usually described in litres. Dividing by 1000 changes cm³ into litres.
How do you level water between two tanks? Add the two base areas, because the water ends up standing on both. The total volume divided by that combined base area gives the depth in each tank.