Fixed end condition on mortgage calculation

Author: dabeaz

Notes/01_Introduction/03_Numbers.md

@@ -234,10 +234,11 @@ The output should look something like this:
 4 10736.44 497581.83
 5 13420.55 496970.98
 ...
-308 875705.88 674.44
-309 878389.99 -2006.86
-Total paid 878389.99
-Months 309
+308 874705.88 2971.43
+309 877389.99 299.7
+310 880074.1 -2383.16
+Total paid 880074.1
+Months 310
 ```
 
 ### Exercise 1.11: Bonus

Solutions/1_10/mortgage.py

@@ -15,7 +15,7 @@
     principal = principal * (1+rate/12) - payment
     total_paid = total_paid + payment
 
-    if month >= extra_payment_start_month and month <= extra_payment_end_month:
+    if month >= extra_payment_start_month and month < extra_payment_end_month:
         principal = principal - extra_payment
         total_paid = total_paid + extra_payment