Added Solution

 Added Solution for Problem 20

Project Euler/Problem 20/sol1.py

@@ -0,0 +1,27 @@
+# Finding the factorial.
+def factorial(n):
+    fact = 1
+    for i in range(1,n+1):
+        fact *= i
+    return fact
+
+# Spliting the digits and adding it.
+def split_and_add(number):
+    sum_of_digits = 0
+    while(number>0):
+        last_digit = number % 10
+        sum_of_digits += last_digit
+        number = int(number/10) # Removing the last_digit from the given number.
+    return sum_of_digits
+
+# Taking the user input.
+number = int(input("Enter the Number: "))
+
+# Assigning the factorial from the factorial function.
+factorial = factorial(number)
+
+# Spliting and adding the factorial into answer.
+answer = split_and_add(factorial)
+
+# Printing the answer.
+print(answer)

Project Euler/README.md

@@ -52,3 +52,7 @@ PROBLEMS:
 
 16. 2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
     What is the sum of the digits of the number 2^1000?
+20. n! means n × (n − 1) × ... × 3 × 2 × 1
+    For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
+    and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
+    Find the sum of the digits in the number 100!