Final answer:
To calculate the probability of solving 120-140 crossword clues in 30 minutes, additional statistical data such as the standard deviation is required. Since this information is not provided, an exact probability cannot be determined. The question falls under probability and statistics within mathematics.
Step-by-step explanation:
The question you've asked pertains to probability and problem-solving abilities which can improve with practice, such as through solving puzzles like sudokus. To answer your question about the probability of solving 120-140 crossword clues in 30 minutes based on your average, we would need more statistical information such as the variance or standard deviation of the number of clues you solve. This kind of problem typically requires knowledge of probability distributions, often solved using the principles of a normal distribution in statistics.
Without such information, however, it is not possible to calculate an exact probability. The concept here is similar to determining how likely a student is to guess more than 75% of the questions correctly on a multiple-choice exam by chance, or understanding the distribution of the number of events someone volunteers for each month.
In essence, this is a statistics problem that seeks to quantify the likelihood of an event occurring within a specified range, given a known average or expected value.