宏观经济题目求解

• Suppose that the income     velocity of money is constant, the money supply grows at 5% per year,     income is growing at 2% per year and the real interest rate is 4%
  

a)   Find thenominal interest rate.

b)   Find by howmuch the nominal interest rate varies when the Central Bank increases the moneygrowth rate by 2% a year.

c)   Suppose thatthe income growth falls to 1% a year. What will happen to the inflation rate? Whatshould the Central Bank do to keep inflation constant at 3%?

答案：

a)nominal interest rate = 7%(b)nominal interest rate varies by 2%(c) Inflation will rise.Central banks should reduce money supply by 1% to keep inflation constant
请大牛指点下答案怎么求出来的，能否给详细说明下,我可以追加分数。谢谢大牛们啦。。：）（我知道有个M*V=P*V公式，但这题目貌似不能用）

a. 实际利率4%=名义利率？ - 通胀率5% + 名义收入增长率2%
   名义利率=4+5-2=7%

b.实际利率4%=名义利率 ？-通胀率2% + 名义收入增长率2%
  名义利率=4+2-2=4%
  名义利率变化=7-4=3个百分点

  【题目中如果是在5%的基础上再增加货币供应量2% 则，
  名义利率为4+（5+2）-2=9%
  名义利率变化=9-7=2个百分点】


c  实际利率4%=名义利率7- 通胀率？+ 名义收入增长率1%
   通胀率？=7-4+1=4%
  与央行目标3%的差距为 4%-3%=1%
   

顶起，求解决

再顶一个～就大师解决

没人知道怎么做吗？

没人回答，自己推了下。
我想了下大概应该是这样做，请各位大牛看看对不对。
a)根据MV=PY，所以，%changing in M+%changing in V=%changing in P + %changing in Y。
那么这里的money supply grows at 5%(%M), income is growing at 2%(%Y)， %M+V%= %P+%Y,
题目说velocity 是constant的，所以 5%+0%=%P+2%

因此 %P=5%-2%=3% (%Changing in P 就是%changing in inflation rate)
又右fisher equation i=r+π，real interest rate i=4%
得出 i=3%+4%=7%

后面两问这这样推出来，不写这了，各位大牛我这样说的对不对？