Answer:
The principal amount be when he must begin repaying his loan is $22383.911.
Step-by-step explanation:
Given : Upon graduation from college, Warren Roberge was able to defer payment on his $22,000 student loan for 3 months. If the interest is 6.94 % compounded monthly.
To find : What will the principal amount be when he must begin repaying his loan?
Solution :
Using compound interest formula,

Where,
A is the amount
P is the principal P=$22,000
r is the rate r=6.94%=0.0694
t is the time t=3 months
Into years, 
n is the number of period n=12
Substitute the value in the formula,





The principal amount be when he must begin repaying his loan is $22383.911.