Incorrect
Explanation
Between 1 and 100, the digit 9 occurs in 9, 19, 29, 39, 49, 59, 69, 79, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 and 99.
Solve this puzzle
Maggie is 21, and her brother Charlie is double her age. How old will Charlie be when Maggie is 40?