Answer:
29
Explanation:
To find the lower quartile of each you need to find the median to split them into 2 groups (upper and lower quartile).
Lower quartile of Set A: 73, 75, 79, 81, 84, 85
Lower quartile of Set B: 47, 49, 51, 51, 55, 56
Now you find the median of the 2
Set A: 80
Set B: 51
Lastly you subtract A & B and get 29