Question

To take a simplified example, if you have a $20,000 student loan at a 4.29% interest rate, you would have been charged a total of $3,722 in interest during your four years in college. If you make no interest payments until you graduate, at that time your loan principal would be $23,722, which means the monthly payment during your 10-year payback period would rise from $205 to $243, and you would end up paying $1,152 more in total interest payments.

How did she get these values?

Answer 1

"if you have a $20,000 student loan at a 4.29% interest rate, you would have been charged a total of $3,722 in interest during your four years in college. If you make no interest payments until you graduate, at that time your loan principal would be $23,722"

EXPLANATION
Using financial calculator
N=4*12
I/Y=4.29%/12
PV=-20000
PMT=0
CPT FV=23722

Hence, Interest=23722-20000=3722

"which means the monthly payment during your 10-year payback period would rise from $205 to $243"

EXPLANATION

Step 1: New monthly payments
Using financial calculator
N=12*10
I/Y=4.29%/12
PV=-23722
FV=0
CPT PMT=243

Step 2: Original monthly payments
N=12*10
I/Y=4.29%/12
PV=-20000
FV=0
CPT PMT=205

"and you would end up paying $1,152 more in total interest payments"

EXPLANATION

This figureI believe is incorrect