Answer:
Median : 59
Lower quartile : 53
Upper quartile : 66
Least age: 41
Greatest age: 79
Explanation:
In a ordered list, the median is the number at the half position. With 23 numbers, the half position the 12th number (there are 11 number above and blow it)
41 42 44 48 52 53 53 53 56 57 57 59 60 61 63 64 64 66 67 69 74 77 79
The lower quartile is the number at the half position, only considering the first data points until the median.
41 42 44 48 52 53 53 53 56 57 57
The upper quartile is the number at the half position, only considering the data points after the median.
60 61 63 64 64 66 67 69 74 77 79
The least and greatest ages are easily found.