Cristiana uses $25,000 to purchase a 25 month cd (certificate of deposit) that pays 2.47%
compounded monthly

Principal amount 25000 
Interest rate 2.47 percent per year = 0.0247 
number of times compounded per year 12 
Number of years 2 
Amount after 25 months = 25000 ( 1 +0.0247 / 12)^(25) 
= 25000(1.002058333)^(25) 
Amount after 2 years = 26318.74 

b) 
26318.74-25,000 = 1,318.74 

2) 
Future amount 32349.72 
Interest rate 4.27 percent per year = 0.0427 
Number of times compounded per year 365 
Number of years 18 
Amount invested in 18 years = 32349.72 / ( 1 +0.0427 / 365)^(6570) 
= 32349.72 / (1.00011698630137)^(6570) 
Amount invested before 18 years = 15000.00