Explanation:

Let the numbers be a, a + 2, a + 4,......a(n)
This forms an Arithmetic Progression AP
General term: a + (n-1)d
here d = 2
and n = 49
Now,
Sum of n terms in AP is given by:
Sum = n/2 [ 2a + (n-1)d ]
Average of 41 numbers is 49
Average = Sum of numbers / Total numbers
41 = Sum / 49
Sum = 41 x 49 = 2009
Putting this sum in our formula, we get
2009 = 49/2 [ 2a + (49 - 1)2 ]
4018 = 49 [ 2a + 96 ]
82 = 2a + 96
2a = -14
a = -7
Largest number is 49th number
49th number is = a + (n-1)d
-7 + 48(2) = 89
Largest number is 8