Seven of them.
Exactly 8 of them
15s-15 = 0
The coordinates 15S, 75W represent a location in Peru, in or near Poroma on the Panamericana Sur.
Two 15s' equals 30.
12r - 15s - r + 3s = 11r -12s
15s=58.5 s=58.5/15 s =3.9
550 divided by 15 equals 36 with a remainder of 10.
12 15s = 180.180 is an integer and not a fraction. However, it can be expressed in rational form as 180/1.