Answer 1

The cumulative frequency for the given data is calculated as follows

Class interval	Frequency	Cumulative frequency
0 - 10	5	5
10 - 20	x	5+ x
20 - 30	20	25 + x
30 - 40	15	40 + x
40 - 50	y	40+ x + y
50 - 60	5	45 + x + y
Total (n)	60

From the table, it can be observed that n = 60
45 + x + y = 60
x + y = 15 (1)
Median of the data is given as 28.5 which lies in interval 20 - 30.

Therefore, median class = 20 - 30

Lower limit (l) of median class = 20

Cumulative frequency (cf) of class preceding the median class = 5 + x

Frequency (f) of median class = 20
Class size (h) = 10

`"Median" = l + (((n/2)-cf)/f)xxh`

28.5 = 20 + [(60/2-(5+x))/20]xx10

8.5 = ((25-x)/2)

17 = 25 - x

8 + y =  15

y = 7
Hence, the values of x and y are 8 and 7 respectively.