Please help me with this question.

Question 3 (10 points). Assume that a closed economy is described by the IS curve Y = 3,600 + 3G-27-150r and the LM curve Y= 2 M / P + 100r [or r = 0.01Y - 0.02 (M / P)]. The investment function for this economy is 1,000 -50r. The consumption function is C=200 + (2/3)(Y-T). Long-run equilibrium output for this economy is 4,000. The price level is 1.0. Assume that government spending is fixed at 1,200. The government wants to achieve a level of investment equal to 900 and also achieve Y = 4,000. What level of r is needed for / = 900? What levels of 7 and M must be set to achieve the two goals? What will be the levels of private saving, public saving, and national saving