Answer:
between 22 an 25 beats
Explanation:
If this lady need to present a heart rate between 135 and 155 beats per minute while she is exercising.
To calculate the beats in 10 sec, is with a simple rule of 3:
If in 60 sec = 135 beats
10 sec = x X= (10 x 135)/60 = 22 beats
And then calculate the higher range
If in 60 sec = 155 beats
10 sec = x x = (10 x 155)/60 = 25 beats