This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Friday, February 05, 2010

Ai Tong Sch 2009 P6 CA1 Math Paper 2 Q9

A snail fell into a well that is 300 cm deep.
In the first hour, it climbed 80 cm up the well.
In the second hour, it climbed 70 cm up the well.
Each hour, it managed to climb 10 cm less than the hour before.
How many hours did it take to climb out of the well?

Solution

1st h --> 80 cm
2nd h --> 70 cm
3rd h --> 60 cm
4th h --> 50 cm
5th h --> 40 cm

(80 + 70 + 60 + 50 + 40) cm = 300 cm
--> 5 hours

Answer: 5 h

3 comments:

小小 said...

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趙惠萍 said...

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ispomyju said...

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