Answer:
36
Explanation:
⇒The question is on third quartile
⇒To find the third quartile we calculate the median of the upper half of the data
Arrange the data in an increasing order
20, 21, 24, 25, 28, 29, 35, 37, 42
Locate the median, the center value
20, 21, 24, 25, 28, 29, 35, 37, 42
The values 20, 21, 24, 25 ------------lower half used in finding first quartile Q1
The value 28 is the median
The vlaues 29, 35, 37, 42...............upper half used in finding 3rd quartile Q3
Finding third quartile Q3= median of the upper half
upper half= 29,35,37,42
median =( 35+37)/2 = 36