To determine how many people could not go on the ride, we need to find the total number of people whose heights are less than 54 inches (which is equivalent to 4 feet 6 inches). We'll examine the heights represented in the histogram:
- 30 to 33 inches: 2 people
- 33 to 36 inches: 0 people
- 36 to 39 inches: 3 people
- 39 to 42 inches: 0 people
- 42 to 45 inches: 11 people
- 45 to 48 inches: 23 people
- 48 to 51 inches: 7 people
- 51 to 54 inches: 5 people
Next, we add up the frequencies of these heights:
\[ 2 + 0 + 3 + 0 + 11 + 23 + 7 + 5 = 51 \]
Thus, the total number of people who could not go on the ride is 51.
Final answer: 51.