145 people were surveyed to find out whether they like or dislike Products A and B. How many like product A?
It is not mentioned whether there are people who didn't opine. Considering that there are some who might not have opined we have to find people who like only A and people who liked both A and B.
(1) 123 people disliked at least one of the two products
It means same 123 people liked at least one of the two products. So, 14-123 = 22 people like both A and B. Hence people who liked A = 22 + 123 - x where x is number of people who liked B.
And 0 ≤ x ≤ 123.
INSUFFICIENT.
(2) 78 people liked product A but did not like product B
People who liked only A = 78. As it is not possible to find people who liked both A and B. Hence
INSUFFICIENT.
Together 1 and 2
Here 123 - x = 78
x = 45
Hence people who like A = 22 + 78 = 100
People who liked only B = 45
SUFFICIENT.
PS: Liking just don't mean people disliked other product or vice-a-versa.
Also, it is assumed that all 145 people surveyed answered positively without any neutral cases.
_________________
Ephemeral Epiphany..!
GMATPREP1 590(Q48,V23) March 6, 2019
GMATPREP2 610(Q44,V29) June 10, 2019
GMATPREPSoft1 680(Q48,V35) June 26, 2019