please help me on these question

The Production Possibility Frontier for an economy is given by y = 20 If this economy is producing 4 units of good x, then its MRT is equal to A. 1/2 B. 12 ()c. 16 D. 20 )E. Not enought information to tell IThe Production Possibility Frontier for an economy is given by y = 40 - 12X. If this economy is producing 10 units of good x, then its MRT is equal to Oo 1/2 4 10 Not enough information to determine