There are 23 * 4 = <<23*4=92>>92 seats on this bus.
After the first stop, there are 16+15 - 3 = <<16+15-3=28>>28 people on the bus.
After the 2nd stop, there are 28+17 - 10 = <<28+17-10=35>>35 people on the bus.
So there are 92 - 35 = <<92-35=57>>57 empty seats on the bus after the 2nd stop.
#### 57