Correct Answer - Option 1 : 7 : 350
The logic follows here is :
(First number)3 + (First number) = Second number.
4 : 68
43 + 4 = 64 + 4 = 68.
Similarly,
(1). 7 : 350
73 + 7 = 343 + 7 = 350.
(2). 3 : 27
33 + 3 = 27 + 3 = 30 ≠ 27.
(3). 5 : 135
53 + 5 = 125 + 5 = 130 ≠ 135.
(4). 6 : 225
63 + 6 = 216 + 6 = 222 ≠ 225.
Hence, the correct answer is "7 : 350".