Total test = 5
Total participants = 51
Total number of selection that can be made = 51 * 5 = 255


Target question => Which of the brands was deemed the better brand?


Statement 1 => Brand x was chosen by a total of 155 participant
The better brand was determined by the total outcome of each test and not the total number of participants that selects the brand
If the 155 votes for brand x was from a uniform distribution over all the five test x may be selected as the better brand else, it is possible for y to be the better brand. The information provided is not enough to arrive at a definite answer. Statement 1 is NOT SUFFICIENT


Statement 2 => One brand won three of the first from taste tests
The winning brand could either be brand x or brand y three of the first four tests. The information provided was not enough to arrive at a definite answer. Statement 2 is NOT SUFFICIENT


Combining both statements together => With the information from both statements, the winning brand could be either brand x or brand y. Since there is no definite answer, both statements combined together ARE NOT SUFFICIENT


Answer = E