Answer:
116 more people
Step-by-step explanation:
Let a, b, c signify the numbers of subscribers who watched 1, 2, and 3 videos, respectively. So we can say that:
a +b +c = 312 this means that there are 312 subscribers, total
a +2b +3c = 740 this means that there were 740 total views
Next, deduct the double the first equation from the second.
(a +2b +3c) -2(a +b +c)
= (740) -2(312)
this will give us: c -a = 740 -624 = 116
Therefore, 116 more people watched all three videos than watched one video.
hope this helps