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.

Monday, February 02, 2009

Tao Nan School P5 SA2 2007 Math Q46

The table below shows the rates of charges for water consumption.

First 5 cubic metres ----- $1.50 per cubic metre
Next 5 cubic metres ----- $1.75 per cubic metre
Every additional 1 cubic metre or part thereof ---- $2.00 per cubic metre

a) In the month of June, Family A used 18 cubic metres of water. How much did Family A pay for their water bill?

b) Family A’s water bill for July was $48.25. How much water was used?

Solution


a)
Charges for 18 cubic metres -----

First 5 cubic metres ----- $1.50 x 5 = $7.50
Second 5 cubic metres ----- $1.75 x 5 = $8.75
Last 8 cubic metres ----- $2 x 8 = $16.00

Total charges ----- $7.50 + $8.75 + $16 = $32.25

Answer: The family paid $32.25


b)
First 10 cubic metres cost ----- $7.50 + $8.75 = $16.25

48.25 - $16.25 = $32

$32 was charged at a rate of $2 per metre cube -----
$32 divided by $2 per metre cube = 16 cubic metres

Total consumption ----- 10 + 16 = 26

Answer: 26 cubic metres of water was used.

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