The given data in ascending order is 7, 10, 15, x, y, 27, 30
Median = (n+1/2)th term = (7+1/2) = 4th term = x
∴ x = 17 by problem
When 50 is added, the data becomes 7, 10, 15, 17, y, 27, 30, 50
Median = \(\frac {((\frac n2) + (\frac n2+1))}{2}\) terms
18 = 17 + y/2 (by problem)
17 + y = 36 y = 36 – 17 = 19