MATHS WEEK 2015 - Day 4 Problems

Here are your challenges for today:

Junior Problem:

When Miss Breen teaches in Room 14 she promises to give stickers to the students who finish their homework. 14 students hand their homework into Miss Breen. She gives their teacher Whaea Donna 28 stickers to hand out fairly between the 14 students. How many stickers will each student get?

Senior Problem:

Whaea Oronsay is having trouble with the school bus on a trip to the snow. She notices that after the bus reaches a speed of 110km/hr, every hour after that the bus's speed automatically decreases by 10%. How many hours of driving would it take before the bus is only able to drive at a speed less than 30km/hr.

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Students: Write your answer in the comment section with your name and class.

Teachers: If you have any photos of student thinking please email to Miss Breen 

Come back tomorrow for new challenges!

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Here is Room 6's thinking:

Hi Miss Breen,

We thought today’s problem could be worked out a couple of ways.

Firstly, we knew that 10% of 110 was 11, so we kept subtracting 11 until we got below 30.  This means the bus would drop below 30kmh in the eighth hour.

The second way was a bit more complicated.  The first hour, the bus’ speed decreases by 11kmh (10% of 110kmh).  The bus is now going at 99kmh after one hour.  In the second hour, we figured out that 10% of 99kmh is 9.9kmh.  That means that the bus, after two hours, is now going 89.1kmh.  In the third hour, 10% of 89.1kmh is 8.91kmh, so we subtracted that…and so on.  The numbers got really hard to manage, so we ended up having to use a calculator!  J  Anyway, using this method, we worked out that the bus would drop below 30kmh in the 13^th hour.