Which of the following are correct in respect of the system of equations x + y + z = 8, x − y + 2z = 6 and 3x − y + 5z = k ?

1.They have no solution, if k = 15.

2.They have infinitely many solutions, if k = 20.

3.They have unique solution, if k = 25.
Select the correct answer using the code given below :

Mathematics 2016 NDA Mathematics 2016 NDA 2016

Options