After the change, Richard will buy more of both goods.

After the change, Richard will buy fewer apples and more oranges.

After the change, Richard will buy more apples and fewer oranges.

After the change, Richard will buy fewer of both goods.

If income effect and own substitution effect of this price change work in the opposite direction, then the good x is necessarily a normal good.

If income effect and own substitution effect of this price change work in the opposite direction, then the good x is necessarily a Giffen good.

If income effect and own substitution effect of this price change work in the same direction, then the good x is necessarily inferior.

If income effect and own substitution effect of this price change work in the same direction, then the good x is necessarily an ordinary good.

 positive if and only if orange is an inferior good.

positive if and only if orange is a normal good.

zero because Eva’s income didn’t change.

positive if and only if orange is an ordinary good.

The change in demand for good x due to this price change's substitution effect is equivalent to a movement between the points on Hicksian demand H_x(p¹_x, p_y, u⁰) and H_x(p⁰_x, p_y, u⁰).

The change in demand for good x due to this price change's substitution effect is equivalent to a movement between the points on Hicksian demand H_x(p¹_x, p_y, u¹) and H_x(p⁰_x, p_y, u¹).

The change in demand for good x due to this price change's substitution effect is equivalent to a movement between the points on Hicksian demand H_x(p¹_x, p_y, u⁰) and H_x(p¹_x, p_y, u¹).

The change in demand for good x due to this price change's substitution effect is equivalent to a movement between the points on Hicksian demand H_x(p⁰_x, p_y, u⁰) and H_x(p⁰_x, p_y, u¹).