Lesson 10 of 15
A rate is a ratio with units on it
Show on a big screenA scoreboard says 48 runs off 8 overs. What is the rate?
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Step 1 of 3
- 48 runs, 8 overs.
- Runs an over: 48 ÷ 8 = 6.
- Divide the other way: 8 ÷ 48 is about 0.17 overs a run. It is a different rate.
The rule
The rate is 6 runs an over.
A rate compares two different kinds of amount. It keeps its units. Examples are runs and overs, or kilometres and hours.
- A bus covers 180 km in 3 hours. The rate is 180 ÷ 3 = 60 km an hour.
- At that rate, 4.5 hours is 4.5 × 60 = 270 km.
- To compare two rates, write both in the same unit.
- 300 g costs ₹240. In kilograms, 300 g is 0.3 kg. So ₹240 ÷ 0.3 = ₹800 a kilogram.
Watch out!
Match the units first. 120 km in 90 minutes is 120 km in 1.5 hours. That is 120 ÷ 1.5 = 80 km an hour.
Try the lab to finish this lesson.