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2 files changed, 17 insertions, 3 deletions

diff --git a/finance/discount_time_value.py b/finance/discount_time_value.py
new file mode 100644
index 0000000..d3b88df
--- /dev/null
+++ b/finance/discount_time_value.py
@@ -0,0 +1,14 @@
+
+
+def npv(pays, r):
+    return sum([pay/((1+r)**(i+1)) for i, pay in enumerate(pays)])
+
+
+if __name__ == '__main__':
+    pays = [236.8, 236.8+1000]
+    r = 0.2368
+    print(npv(pays, r))
+
+    pays = [192.06, 192.06+1100]
+    r = 0.1746
+    print(npv(pays, r))
diff --git a/finance/equal_principal_interest.py b/finance/equal_principal_interest.py
index 035fd8c..2954260 100644
--- a/finance/equal_principal_interest.py
+++ b/finance/equal_principal_interest.py
@@ -12,8 +12,8 @@ def monthly_analysis(p, r, n):
 
 
 if __name__ == '__main__':
-    p = 600000
-    r = 0.06
-    n = 20*12
+    p = 2000000
+    r = 0.055
+    n = 30*12
     monthly_analysis(p, r, n)