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a man moves to lie on an island in Europe. He has a choice of two water companies:

Manana Water: No standing charge. Pay £0.06 per m3 of water used.

Channel Water: Standing Charge: £30 every 3 months

£0.02 per m3 of water used

Special offer: 20% off your first bill.


he estimates that he uses 700m3 of water every 3 months. which company should he choose?

Verified Answer :

FletchXYZ

Manana would be the best choice in the long run—see all my work below.

Regular prices:

Manana: \(700*.06=42\) £/3mos
Channel: \((700*.02)+30=44\) £/3mos

However, with the 20% discount on Channel Water, the first three months would look like:

(NOTE: This may be an overly complicated equation, but it's how it works out in my head.)

\((((\frac{700}{3})2*.02)+30)-((\frac{700*.02+30}{100})20)=30.53\) £ for the first three months.

Manana:
\(4*42=168\) £/year

Channel:
\((2.75*44)+30.53=151.53\) £ for the first year, and \(4*44=176\) £/year afterwards.

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