Answer:
Option (A) is correct.
Explanation:
Qx = 1000 - 10Px + 0.1I + 10Py
Suppose income of the consumer and the price of good x remains constant at
I = $100
Px = $10
Initial price of good y, Py = 10
So,
Qx = 1000 - 10(10) + 0.1(100) + 10(10)
= 1000 - 100 + 10 + 100
= 1,010 units
If price of good y increases to $20, then,
Qx = 1000 - 10(10) + 0.1(100) + 10(20)
= 1000 - 100 + 10 + 200
= 1,110 units
This will results in an increase in the quantity demanded for good x which shows that there is a positive relationship between the price of good y and quantity demanded for good x.
This indicates that good x and good y are substitute goods.