I need to be able to Modify anArray so that any grades of 48 or 49 change to 50 and any grades of 78 or 79 change to 80

Question

I need to be able to Modify anArray so that any grades of 48 or 49 change to 50 and any grades of 78 or 79 change to 80.

Let grades1 = [70, 78, 49, 50, 81, 48, 79