Nancy’s heart beats were faster. As you can see from the graph, Nancy is currently going at a rate of 1.25 beats per second as opposed to Lee’s 1.2 beats per second. You can figure this out from dividing
Y/x=rate
I can choose any point of the graph which I can divide.
For this case I choose (20,25)
So I divide 25/20 and I will get 1 5/20 rounding to 1 1/4 and then converted to 1.25 beats per second.
Hope that helps!!