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.