Microeconomics 3 Tiffanys utility function is given by the f
Microeconomics
3. Tiffany’s utility function is given by the formula U(x1, x2) = min{2x1, 800x2}. If x1 = x2, which commodity will have a greater marginal utility?
a. x1
b. It is not possible to determine which commodity has higher marginal utility
c. Both x1 and x2 have the same marginal utility
d. x2
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6. What is the slope of the level curves of the function f(x,y)=5x2y3?
a. -(2y)/(3x)
b. -10xy3
c. - 1/(15x2y2)
d. -(3x)/(2y)
e. -(2y2)/(3x2)
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7. For U(x1,x2) = 6x11/3 + x2, preferences are
a. consistent with increasing marginal rate of substitution.
b. consistent with constant marginal rate of substitution
c. not consistent with a utility function.
d. consistent with diminishing marginal rate of substitution.
Solution
3) The correct option is C
In the utility function U(x1, x2) = min{2x1, 800x2} , X1 & X2 are complementary goods , therefore an increase in the consumption of X1 causes an increase in the consumption of X2 . It means an additional quantity of one without increase in the quantity of the other does not yield additional satisfaction .
6) f(x,y)=5x2y3
f1(x) = 10xy3
f1(y) = 5X2 3y2
Slope = f1(x) / f1(y)
slope = 10xy3 / 5X2 3y2
slope = -(2y/3x)
7) The correct option is b
explanation : The utility function represents substitute goods where the number of units of goods X2 must be given up , to have more units of X1 and thereby the total utility of the consumer remains the same by consuming more of goods X1 .

