【正文】 requiring schools to include ‘litter awareness’ as part of citizenship education。 (d) A rise in the demand for bread。 This question is concerned with the supply of oil for central heating. In each case consider whether there is a movement along the supply curve (and in which direction) or a shift in it (left or right). (a) 1. How much would be supplied at a price of 70p per kilo? About 430 000 tonnes per month. 216。 1. Assume that in Table the total market demand for potatoes increases by 20 per cent at each price – due, say, to substantial increases in the prices of bread and rice. Plot the old and the new demand curves for potatoes. Is the new curve parallel to the old one? See Diagram below. As you can see, the curves are not parallel. A constant percentage increase in quantity demanded gives a bigger and bigger absolute increase as quantity increases. 216。 2. The price of blueberries rises and yet it is observed that the sales of blueberries increase. Does this mean that the demand curve for blueberries is upward sloping? Explain. No not necessarily. For example, the price of substitutes such as other soft fruit may have risen by a larger amount. In such cases the demand curve for blueberries will have shifted to the right. Thus although a rise in the price of blueberries will cause a movement up along this new demand curve, more blueberries will nevertheless be demanded because they are now relatively cheaper than the alternatives.Page 38 216。 2. Draw a supply curve for farmer X. Are the axes drawn to the same scale as in Figure ? The supply curve for farmer X will merely plot the relevant two columns from Table . The vertical axis can be drawn to the same scale as in Figure , but a different scale will have to be used for the horizontal axis (. tonnes rather than thousands of tonnes). 41 216。New oil fields start up in production. (b) The demand for central heating rises. (c) The price of gas falls. (d) Oil panies anticipate an upsurge in demand for centralheating oil. (e) The demand for petrol rises. (f) New technology decreases the costs of oil refining. (g) All oil products bee more expensive. (a) Shift right. (b) Movement up along (as a result of a rise in price). (c) Movement down along (as a result of a fall in price resulting from a fall in demand as people switch to gasfire central heating). (d) (e) An expected rise in the price of butter in the near future。 requiring fast food outlets to provide adequate wastebins and encourage their use。 having an antilitter campaign on television or on posters。 (c) A rise in the price of bread。 An increase in leather imports. 216。million rise in national ine (see Diagram ).Page 40 216。 3. What explanations could there be for the quite different shapes of their two demand curves? One explanation could be that Tracey is quite happy to eat rice, pasta or bread instead of potatoes. Thus when the price of potatoes goes up she switches to these other foods, and switches to potatoes when the price of potatoes es down. Darren, by contrast, may not see these other foods as close substitutes and thus his demand for potatoes will be