Permintaan, penawaran, keseimbangan, dan elastisitas
Pearson Edexcel · International GCSE · Economics Topik 2 5:39 Narasi bahasa Inggris · Subtitle bahasa Inggris + 中文 disematkan langsung
Bab-bab
Transkrip
This topic builds one market model.
本主题建立一个市场模型。
Demand and supply meet at the equilibrium price.
需求和供给在均衡价格处相交。
Elasticity then measures how strongly quantity responds to price and to income.
弹性衡量数量对价格和收入变化的反应有多强。
The shared model runs through every worked example.
所有例题都用同一个模型。
Demand is the quantity consumers are willing and able to buy at each price.
需求是消费者在每个价格下愿意并且能够购买的数量。
A change in the good's own price causes a MOVEMENT along the demand curve.
商品自身价格的变化引起沿需求曲线的移动。
A change in any other determinant SHIFTS the whole curve.
其他任何因素的变化使整条曲线移动。
Demand shifts with income, advertising, fashion and tastes, and demographic change.
收入、广告、时尚与偏好以及人口结构的变化都会使需求曲线移动。
Watch related goods. A rise in the price of a substitute shifts demand for this good right. A rise in the price of a complement shifts it left.
注意相关商品：替代品价格上升，本商品的需求右移；互补品价格上升，本商品的需求左移。
Supply is the quantity producers are willing and able to sell at each price.
供给是生产者在每个价格下愿意并且能够出售的数量。
Own-price changes move along the curve.
自身价格的变化引起沿曲线移动。
Costs of production, technology, indirect taxes, subsidies and natural factors shift it.
生产成本、技术、间接税、补贴和自然因素使曲线移动。
Better technology shifts supply right; indirect taxes shift it left.
技术进步使供给右移；间接税使供给左移。
Equilibrium is where demand meets supply.
均衡是需求与供给相交的地方。
Set 140 minus 2P equal to 20 plus 4P.
令 140 减 2P 等于 20 加 4P。
Then 120 equals 6P, so the price is 20.
于是 120 等于 6P，价格为 20。
Substitute back: 140 minus 40 gives a quantity of 100 items a day.
代回去：140 减 40，数量为每天 100 件。
The curves meet at the equilibrium: a price of 20 and 100 items.
两条曲线在均衡处相交：价格 20，数量 100。
At a price of 12, consumers want 116 but producers offer 68: a shortage of 48, which bids the price up.
价格为 12 时，消费者想买 116，生产者只供给 68：短缺 48，价格被抬高。
At 25, producers offer 120 but consumers want 90: a surplus of 30, which pushes the price down.
价格为 25 时，生产者供给 120，消费者只想买 90：过剩 30，价格被压低。
When demand rises, the curve shifts right, and both the equilibrium price and quantity rise.
需求增加时，曲线右移，均衡价格和数量都上升。
Here both rise: the price to 22 and the quantity to 108.
这里两者都上升：价格升到 22，数量升到 108。
When supply rises instead, quantity rises but price falls.
如果是供给增加，数量上升但价格下降。
Price elasticity of demand is the percentage change in quantity demanded divided by the percentage change in price.
需求价格弹性等于需求量变化的百分比除以价格变化的百分比。
Price rises from 20 to 22, plus 10 percent.
价格从 20 升到 22，上涨百分之 10。
Quantity falls from 100 to 96, minus 4 percent.
数量从 100 降到 96，下降百分之 4。
PED is minus 4 over 10: minus 0.4.
PED 等于负 4 除以 10，即负 0.4。
Demand is inelastic.
需求缺乏弹性。
Read a PED value in five ranges.
PED 的值分五个区间来读。
Zero is perfectly inelastic, a vertical curve.
0 是完全无弹性，曲线垂直。
Between 0 and minus 1 is inelastic.
0 到负 1 之间缺乏弹性。
Minus 1 is unitary.
负 1 是单位弹性。
Beyond minus 1 is elastic.
超过负 1 富有弹性。
Infinite is perfectly elastic, a horizontal curve.
无穷大是完全弹性，曲线水平。
Total revenue is price times quantity.
总收入等于价格乘以数量。
At a price of 20, revenue is 2000.
价格为 20 时，收入为 2000。
At 22, it is 2112: the price rise raised revenue, which proves demand is inelastic there.
价格为 22 时，收入为 2112：提价使收入增加，证明此处需求缺乏弹性。
On this curve revenue peaks at 2450, at a price of 35, where PED is unitary.
在这条曲线上，收入在价格为 35 时达到最大值 2450，此处 PED 为单位弹性。
Price elasticity of supply is the percentage change in quantity supplied divided by the percentage change in price.
供给价格弹性等于供给量变化的百分比除以价格变化的百分比。
Price rises from 20 to 24, plus 20 percent; quantity supplied rises from 100 to 116, plus 16 percent.
价格从 20 升到 24，上涨百分之 20；供给量从 100 增加到116，增加百分之 16。
PES is 16 over 20: plus 0.8, inelastic supply.
PES 等于 16 除以 20，即正 0.8，供给缺乏弹性。
Manufactured products tend to have more elastic supply: firms hold stocks, have spare capacity and can retool quickly.
制成品的供给往往更有弹性：企业有库存、有闲置产能、能迅速改换生产。
Primary products are less elastic: crops have growing periods, they perish, and land is fixed.
初级产品弹性较小：农作物有生长期，容易腐烂，土地也是固定的。
Income elasticity of demand is the percentage change in quantity demanded divided by the percentage change in income.
需求收入弹性等于需求量变化的百分比除以收入变化的百分比。
Above 1, the good is a luxury.
大于 1 是奢侈品。
Between 0 and 1, a normal necessity.
0 到 1 之间是普通必需品。
Below 0, inferior: demand falls as incomes rise.
小于 0 是劣等品：收入增加时需求反而下降。
Luxury sellers boom with incomes.
奢侈品卖家随收入增长而兴旺。
Demand and supply for cocoa beans begin at P1 and Q1.
可可豆的需求和供给起初在 P1、Q1 处相交。
Heavy rain, drought and a plant disease destroyed much of the harvest, which shifts supply left to S2.
暴雨、干旱和植物病害毁掉了大量收成，使供给左移到 S2。
At the old price there is excess demand, so the price rises to P2 and the quantity falls to Q2.
在原价格下出现超额需求，所以价格升到 P2，数量降到 Q2。
The bar's price rose from 1 dollar to 1 dollar 20: plus 20 percent.
巧克力棒价格从 1 美元涨到 1.20 美元：上涨百分之 20。
Weekly sales fell from 500,000 to 450,000: minus 10 percent.
每周销量从 50 万降到 45 万：下降百分之 10。
PED is minus 10 over 20: minus 0.5, inelastic.
PED 等于负 10 除以20，即负 0.5，缺乏弹性。
So revenue rose from 500,000 to 540,000 dollars a week.
所以每周收入从 50 万美元增加到 54 万美元。
For a further rise: demand is inelastic, so revenue rises, costs are high, and rivals face the same costs.
支持再次提价：需求缺乏弹性，收入会增加；成本高；竞争对手面临同样的成本。
Against: PED is measured over one small change; at a higher price buyers may switch to other snacks.
反对：PED 只是在一次小的价格变化中测得的；价格更高时，买家可能改买其他零食。
Judgement: a small rise now, but watch rivals' prices and weekly sales.
判断：现在可以小幅提价，但要关注对手的价格和每周销量。
Check yourself.
自我检测。
When a complement's price rises, demand shifts left.
互补品价格上升，需求左移。
At a price of 12, excess demand is 116 minus 68: 48.
价格为 12 时，超额需求为 116 减 68，即 48。
If a price rise raises revenue, demand is inelastic.
提价使收入增加，说明需求缺乏弹性。
A negative YED means an inferior good.
YED 为负表示劣等品。