Antonio's heart beats 255 times in 3 minutes. What is his heart rate in beats per second?

Answer 1

There are 60 seconds in a minute, so Antonio's heart beats 255 times in 3 x 60 = <<3*60=180>>180 seconds.
Therefore, Antonio's heart rate is 255 / 180 = <<255/180=1.4166666666666667>>1.42 beats per second. Answer: \boxed{1.42}.