Economic Keynesian theory question please help?

Question

Suppose the MPC = 0.60 and government purchases increase by $40 billion. In Keynesian theory, which of the following is true?

a. The TE curve shifts downward by $40 billion and Real GDP decreases by $40 billion.

b. The TE curve shifts upward by $40 billion, and Real GDP increases by $40 billion.

c. The TE curve shifts downward by $40 billion, and Real GDP decreases by $100 billion.

d. The TE curve shifts upward by $40 billion, and Real GDP increases by $100 billion.

Answer 1

d. The TE curve shifts upward by $40 billion, and Real GDP increases by $100 billion.

40/(1-0.6)=40/0.4=+100