precalc

I will assume tan y    is   tan S

Tans = opp / adj   =   x / (x+14)  = 8/15   

                                  8(x+14)  = 15x

                                   x = 16

            

Pythag theorem      16^2  +   30^2  = QS^2     solve for QS

 

cos RQS = adj / hyp = 16/(the value you found for QS above) = .........