solve this fortran program clearly

QUESTION 3 20 (a) 17 Marks] Write a subroutine that receives from the main program a l of real variables and returns the geometric and harmonic means of the array. 1-D array of size n Geometric mean = ( 1.x2 ...-m )1 Tn Harmonic meanT xn x1 x2 x3 (Do not write the main program. The main program will follow in part (b))