Note that the graph shows us that the minimum and maximum value of the ages are 40 and 75, respectively.
We can count the number of bars on the histogram. We see that the are 7 bars in total.
Each bar consider the same age span, so that means that each bar represent an age span of the same amount of years.
To calculate this range, we first find the difference between the maximum and the minimum, that is
Now, we divide this number by the total number of bars. That is
So, each bar represents a range of 5 years .
Since the minimu is 40, this means that the first bar should represent ages from 40-44. Note that despite the difference between 44 and 40 is only 4, since we are including age 40 in the first bar, we have numbers 40,41,42,43,44 (5 numbers ) associated to the first bar.
This means that for the next one, which is the range T we are looking for, the correspondent age range should be 45-49