Page 1157 - AP Computer Science A, 7th edition

34. (D) The computer should find the number in no more than
seven tries. This each successive
(1) (2) (3) (4) (5) (6) (7)
is because the guessing interval is halved on try:
100÷2=50 50÷2=25 25÷2=13
13÷2=7 7÷2=4 4÷2=2 2÷2=1
numbers left to try numberslefttotry numberslefttotry numbers left to try numbers left to try numbers left to try number left to try
Seven iterations of the loop leaves just 1 number left to try!