Hans has $27 which he decides to spend on x and y. Commodity x costs $16 per unit and commodity y costs $10 per unit. He has the utility function U(x, y) = 5x^2 + 2y^2 and he can purchase fractional units of x and y. Hans will choose (A)will only buy 1 unit of x.
Explanation:
Given the utility function U(x, y) = 5x^2 + 2y^2 a
By Applying Lagrange we get
L(x,y,µ)=5x²+2y²+µ(16x+10y-27)
dL/dx=10x+µ16=0
dL/dy=4y+µ10=0
dL/µ=16x+10y-27=0 ---------->(iii)
From one and two equations we get
25x=16y
x=0.64y
Substituting the value of x in the third equation we get
16( 0.64y)+10y-27=0
Further simplifying we get y
20.24 y=27
y=27/20.24=1,3 units
16x+10y=27
16 x+13-27=0
16 x=14
x=14/16=0.8 units that do not reach one unit
Hans will choose (A)will only buy 1 unit of x.