把一个人的阶段分为年轻和老，当他年轻的时候，可以挣10000，当他老的时候花光他所储蓄。现在利率为11%。假设他现在效用函数和未来消费是U（c1,c2)=0.23c1^0.2 c2^0.3.
在图上表示出预算线和效用函数，show his optimal consumption point.
what will be his optimal current consumption
if interet rate increase 10%, what will be his consumption decision
quantify the income effect and substitution effect.

求各位大大提点几下