Suppose that 11 of a certain batch of calculators have a def

Suppose that 11% of a certain batch of calculators have a defective case, and that 13% have defective batteries. Also 3% have both a defective case and defective batteries. A calculator is selected from the batch at random. Find the probability that the calculator has a good case and good batteries.

The probability that the calculator has a good case and good batteries is _______.

Solution

calculator with good case = 1 - defective case = 1 - 0.11 = 0.89

good batteries = 1 - defective batteries = 1 - 0.13 = 0.97

defective case and defective batteries = 0.03

good case and good batteries = 1 - 0.03 = 0.97

The probability that the calculator has a good case and good batteries is 0.97