The resting heart rate for healthy adult horses averages 46 beats per minute with a standard deviation of 8 beats per minute. A horse whose resting heart rate is in the upper 10% of the distribution of heart rates may have a secondary infection or illness that needs to be treated. How fast must a healthy horse's heart be beating to fall into this at-risk group? (Use the steps outlined below)

a) Draw a normal curve with the parameters as stated. Shade in the region in the above figure that represents the upper 10% of the distribution.

b) Find the z-score of the (unknown) boundary of the region. Show the calculator function used and all inputs. Round to 2 decimal places.

c) Convert the z-score to a value of x, the original variable.