Answer:
Step-by-step explanation:
Given that there are three variables satisfying the equation
Here each x is given to be a positive integer
i.e. solution set for each of the variable can be any integer from 1 to 20 at most.(because if two other integers are 1 each third has to be 20)
Hence solution set can be of the form
If x1 =1, there are 20 solution sets
If x1 =2,there are 19
...
If x1 =20 there is 1 set
Hence total solutions can be