Elmer's utility function is U(x, y) = min{x, y2}. If the price of x is $10 and the price of y is $15 and if Elmer chooses to consume 4 units of y, what must his income be?
a. $220
b. $100
c. $320
d. There is not enough information to determine his income.
e. There is enough information to determine his income, but I have not seen previously a problem like this. So, the tools I have learnt in class cannot help me.
Can someone please explain to me how to reach the final answer?