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Let’s Practise
The total monthly rainfall recorded in January 2016 was 253 mm. 372 mm of rainfall was recorded in February 2016. The total monthly rainfall recorded in 2016 from January to March was 645 mm.
Find the percentage increase in the total monthly rainfall recorded from January 2016 to February 2016. Correct your answer to 1 decimal place.
Find the percentage change in the total monthly rainfall recorded from February 2016 to March 2016. Correct your answer to 1 decimal place.
The mass of a puppy had increased by 25% of its mass at birth to 5 kg at Week 4. By Week 8, the mass of the puppy increased further by 60% of its mass at Week 4.
What was the mass of the puppy at birth?
What was the mass of the puppy at Week 8 after birth?
In September, Mr Tan’s electricity bill was $65. Mr Baker’s electricity bill was
6
5 of Mr Tan’s electricity bill. In October, Mr Baker’s electricity bill decreased by 30%. Find the decrease in Mr Baker’s electricity bill from September to October.
The marbles in a box are in three colours, red, blue and green. 20% of the marbles are green. 30% of the remaining marbles are blue. There are 168 red marbles in the box.
What percentage of the marbles in the box are blue?
How many marbles are there in the box altogether?
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72 Chapter 4 Lesson 3
