Question

You have torn a tendon and are facing surgery to repair it. The surgeon explains the risks to you: infection occurs in 5% of such operations, the repair fails in 13%, and both infection and failure occur together in 2%. What percent of these operations succeed and are free from infection?

Answer 1

percent of operations succeed and are free from infection = 100 - percent of operations either not successful or not free from infection

infection occurs = 5%

repair fails = 13%

both infection and failure occur together = 2%

percent of operations either not successful or not free from = infection occurs +  repair fails - both infection and failure occur together

percent of operations either not successful or not free from = 5 + 13 - 2

percent of operations either not successful or not free from = 16%

percent of operations succeed and are free from infection = 100 - percent of operations either not successful or not free from infection

percent of operations succeed and are free from infection = 100 - 16

percent of operations succeed and are free from infection = 84%