In this challenge, your input will be three lines, each containing a string. The first line will be stored in the variable s1, the second in s2, and the third in s3. Define a variable called joined_with_commas that holds a string with the contents of s1, followed by a comma, followed by s2, followed by a comma, followed by s3.

Answered below.

Explanation:

This challenge is solved using Python programming language.

#First getting the inputs and storing them in #variables s1, s2, s3

s1 = input ("Enter first string: ")

s2 = input("Enter second string: ")

s3 = input ("Enter third string: ")

#Then joining them with commas to make one #string.

joined_with_commas = "$s1 , $s2 , $s3"

print (joined_with_commas)