In: Economics
Murphy was consuming 100 units of X and 50 units of Y . The price of X rose from $2 to $3. The price of Y remained at $4.
(a) How much would Murphyís income have to rise so that he can still exactly a§ord 100 units of X and 50 units of Y ? Assume that Murphy spends all of his income on X and Y .
(b) Now say that Murphyís income falls to $300. If the price of Y is $4, what does the price of X have to fall to in order for Murphy to be able to a§ord 100 units of X and 50 units of Y ?
(c) Now say that Murphyís income falls to $100. If the price of Y is $4, what does the price of X have to fall to in order for Murphy to be able to a§ord 100 units of X and 50 units of Y ?
a) The budget line is given by:
x*Px + y*PY = M
Before price change,
100*2 + 50*4 = M
M = $400
After price change,
100*3+50*4 = M'
300+200=M'
M' = $500
So, income has to rise by M'-M = $500-$400 = $100
b) M = $300
100*Px+50*4 = 300
100*Px =100
Px = 1
The new price is $1. So, the price changes by $1-$2 = -$1
The price should fall by $1 for Murphy to be able to afford 100 units of X and 50 units of Y
c) M = $100
If he consumes 50 units of Y, then expenditure on good Y = $4 * 50 = $200
He is doing more expenditure that what his income is even if he tries to consume only 50 units of good Y.
Therefore, no matter how much the price falls, he cannot afford to consume 100 units of X and 50 units of Y given that his income is $100. This bundle is outside his budget set.