When abdominoplasty costs were $6,000, Dr. Hurwitz treated 300 patients. When they dropped the price to $5,000, customers increased to 400.
What is the elasticity of demand for abdominoplasty using arc elasticity or the midpoints formula (rounded-off to 2 decimal places)?
a. - 1.38
b. - 1.57
c. - 0.157
d. cannot tell
e. none of the above