Given that 175bpm will be decreased by 20bpm, this will make both heart rate count of Kayla and Tia to 155bpm. Since Kayla's target heart rate was 142bpm-179bpm and Tia's target heart rate was 150bpm-183bpm, this makes 155bpm within their THR zone. Therefore, Both Kayla and Tia are in their target heart rate zone.