M3.4.6 For the adult
Rates and speed
Priya walks 6 km in 2 hours. Tariq walks 10 km in 5 hours. Who walks faster?
What this chapter teaches
A rate compares two different kinds of amount. Speed is the distance gone in each unit of time, such as each hour. To compare two buys, find the amount for one coin in each and compare.
Three questions to ask
There is no one right wording. Listen for the idea.
- How do you work out a speed from a distance and a time?
- Why is a bag of 10 kg not always a better buy than a bag of 6 kg?
- If a bus goes at 40 km per hour, how far does it go in half an hour?
After the chapter, the learner can
- Work out a speed in km per hour from distance and time
- Find which of two bags gives more rice for each coin
What they copy into their notebook
Speed is distance ÷ time, in km per hour. Distance = speed × time. For the better buy, find the amount for 1 coin. The bigger bag is not always better.