For each of the following scenarios, use a supply and demand diagram to illustrate the effect of the given shock on the equilibrium price and quantity in the specified competitive market. Explain whether there is a shift in the demand curve, the supply curve, or neither.

a. The MBTA decides to increase the price of a T-token from $1.25 to $1.70, and also increases the price of monthly T-passes. Show the effect on demand, supply and on the equilibrium in the greater Boston area market for used cars. Are T-passes and cars substitutes or complements?

b. America is the biggest producer of corn in the world. Bad weather conditions in the Midwest lead to a very low production of corn in the USA. Show the effect on the world corn market.

c. The US government introduced a price cap on steel a couple of years ago. The excess demand for steel has resulted in many complaints by lobbying groups in Washington, and to please these, the government raises the price cap on steel from $100/ton to $125/ton. This is however still below the free market price of $150/ton. Show the effect on the market for steel.

d. US steel mills buy their coal in Latin America. Show the effect of the above mentioned policy (in (c)) on the Latin American coal market.

e. The popularity of a new fad diet causes consumers' tastes to shift away from bread. Show the effect on the market for butter, which is used mainly when people eat toast.