“Sophie travels 90 miles from Manchester to Birmingham. Altogether the journey takes her 1 hour 40 minutes.
Aside from 20 miles of roadworks on the route, her average speed was 70mph.
What was her average speed through the roadworks?”
Initially my current year 11s wouldn’t attempt a question like this, too many different numbers and not the expected (more straight forward) “a train travels 120km in 4 hours, calculate the speed”.
In one question I saw a diagram which helped break the question down, and now I encourage all my classes to draw a simple diagram to model the problem:
It is basically a straight line split up into different ‘legs’ of the journey (in this case two different parts of the journey roadworks and no roadworks) and then write out “s=“ “d=“ and “t=“ for each leg of the journey.
They fill out the bits they know and then it is clear the bits they need to find out. In my example, the distance with no roadworks can be found by total distance subtract 20 miles of roadworks, then the time can be found using speed and distance:
Then they can find time taken through roadworks to find the average speed:
I find this can be applied to most speed, distance, time questions and as soon as my students get a more complex question like this adding the structure highlights what needs to be calculated in a student friendly way.
Any other suggestions on how to tackle some of the heavier, more complex exam questions the students are now facing?
