Answer: If it is probability, there is a 40% chance that a school will receive a defective calculator if the selections are random.
If the calculators are tested and sorted, there can be 3 selections of 4 calculators sent to schools once the 8 defective ones are removed.
Step-by-step explanation: The question is unclear. Is it about subtracting the bad ones and dividing the good ones? Or is it about Taking chances with the selection of calculators to be sent?
If they subtract: 20-8= 12 left 12÷4= 3 sets of good ones.
If they take chances 8/20 = .4 so there is a 40% chance that a bad calculator will be included in the selection.