Speed Questions. Throughout the years, Speed questions still remain to be one of the most challenging topics feared by most Primary 6 students and parents alike.
Speed questions can come in different forms and difficulties. Although the weightage of Speed questions in the PSLE Math Paper may not be as high, knowing how to solve them can make a significant difference in getting that A* you want.
The Speed Formula
Speed questions that appear in Paper 1 are usually foundational in nature. Most of the time, they can be solved as long as you are armed with the Speed Time Distance formula (Also known as Time Speed Distance formula or Distance Speed Time formula).
Essentially, there are 3 components that are involved.
Speed – A measure of how fast an object travels from one place to another. (usually in m/s or km/h)
Time – Duration of travel
Distance – A measure of how far the object travels
If a car travels at a speed of 60 km/h and you drive it for 2 hours, it would cover a distance of 60 km/h x 2 h which is 120 km.
Hence, the relationship between Speed, Time and Distance: Distance = Speed x Time !
Math Paper 1
Speed questions in Paper 1 will usually provide you with 2 variables out of the 3 (speed, time or distance). Your task is then to solve for the missing third value.
These questions are fairly straightforward. You can find the answers by replacing the known values into the Speed Time Distance formula and working it out.
Math Paper 2
For speed questions that appear in Paper 2, the word problem may involve more complicated events, such as having the 2 objects moving in different directions, travelling some overlapping distance, catching up etc.
This is the part where most students get confused.
Is there a way to help you solve such speed questions easily?
Thankfully, there is.
In the next section, we’ll take a look at this useful problem-solving technique called the “draw a picture” or “draw a diagram” strategy and how it can help you.
What are some of the challenges?
When it comes to solving speed questions, using the “Draw a diagram” strategy is highly recommended.
The main challenge that most students face has to be comprehension. Why?
It is due to one of the 3 reasons below:
- It is hard for them to visualize the scenario described.
- The length of the question is too long.
- Too many things are happening.
How does it help?
Drawing the speed diagram helps you “see” better and gets rid of the confusion!
As you are drawing the diagram, you need to identify the key people/objects involved, the locations and their travel paths. This helps you have a better understanding of the relationship between the various entities and picture the sequence of what happened to who along the way.
Drawing the speed diagram is like describing the solution to the problem.
See how taking away the burden of language helps us focus better on the Mathematical aspects of the problem?
However, since drawings are representations of the problem to help you go through the thought processes, they do not have to represent the problem accurately. We simply need to make sure that we’ve labelled them correctly.
Do check out this video if you want to see this strategy in action!