Answer:
Christopher
He will need to contribute $661.51 every quarter for seven years.
Step-by-step explanation:
a) Data and Calculations:
To save up to $20,000 for a house down payment seven years from now, Christopher needs to save every quarter:
Results 
PMT = $661.51
N (# of periods) = 28 
I/Y (Interest per year) = 2.25 
PV (Present Value) = 0 
FV (Future Value) = $20,000 
 
P/Y (# of periods per year) = 4 
C/Y (# of times interest compound per year) = 4 
PMT made at the of each quarter 
 
Sum of all periodic savings = $18,522.41 
Total Interest = $1,477.59