Exchange Rates & Best Buys Flashcards

All 13 cards in this deck

What does the exchange rate $£1 = €1.15$ mean as a ratio?

pounds : euros $= 1 : 1.15$, so the two amounts are in direct proportion (equal ratios).

How do you convert an amount of pounds into a foreign currency using a given exchange rate?

e.g. convert £40 when $£1 = €1.15$

Multiply by the rate.
$40 \times 1.15 = €46$

How do you convert an amount of foreign currency back into pounds using a given exchange rate?

e.g. convert €69 when $£1 = €1.15$

Divide by the rate.
$69 \div 1.15 = £60$

True or false? To change euros into pounds when $£1 = €1.15$, you multiply the number of euros by $1.15$.

False. You divide by $1.15$; you multiply only when going from pounds to euros.

What are the steps to convert between two currencies using two exchange rates with pounds?

e.g. convert $60 into yen when $£1 = \$1.20$ and $£1 = ¥150$

1. Convert to pounds by dividing: $60 \div 1.20 = £50$
2. Convert from pounds by multiplying: $50 \times 150 = ¥7500$

In a 'best buy' question, what makes one option better value for money?

The one with the lower cost per unit (or the greater amount per pound).

What are the steps to compare two packs using cost per unit?

e.g. 500 g for £2.00 or 800 g for £3.00

1. Divide price by quantity for each: $200 \div 500 = 0.4$p per g; $300 \div 800 = 0.375$p per g
2. The lower cost per unit is better value: the 800 g pack.

How do you compare value for money using the amount obtained per pound?

e.g. 500 g of rice for £2

Divide the quantity by the price: $500 \div 2 = 250$ g per £; the larger amount per £ is better value.

True or false? In a best buy question, the pack with the lower price is the better value.

False. You must compare cost per unit (or amount per pound), since the packs contain different quantities.

How do you find the cost per item of a '3 for the price of 2' style offer?

e.g. 3 tins for the price of 2 at £1.50 each

Divide the total paid by the total number of items received: $£3.00 \div 3 = £1.00$ per tin, then compare with the other offer.

What are the steps to find the cheapest way to buy a required amount sold in fixed pack sizes?

e.g. need 20 eggs; packs of 6 cost £1.20, packs of 12 cost £2.00

1. List combinations giving at least the amount needed: $2\times12$, $12+6+6$, $4\times6$
2. Work out each total cost: £4.00, £4.40, £4.80
3. Choose the lowest total: two 12-packs, £4.00

What are the steps to compare a foreign fuel price per litre with a UK price per gallon?

e.g. abroad €1.20 per litre, UK £5.00 per gallon, $£1 = €1.20$, 1 gallon $= 4.5$ litres

1. Convert the foreign price to pounds: $€1.20 \div 1.20 = £1$ per litre.
2. Convert to the same unit: $£1 \times 4.5 = £4.50$ per gallon.
3. Compare in the same currency and unit: £4.50 < £5.00, so the fuel abroad is cheaper.

True or false? If petrol abroad costs fewer euros per litre than the number of pounds per gallon in the UK, the petrol abroad must be cheaper.

False. Prices can only be compared once both are in the same currency and per the same unit.