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## 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

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.