I do not agree. If you divide 240 by 30, it would be 8 heartbeats, which is absurd. It's impossible for something to survive with 8 heartbeats per 30 seconds.
In order to get the CORRECT answer, divide 240 by 60 seconds.
This would give you 4 heartbeats per second.
Then, multiply it by 30 seconds, which would give you 120 heartbeats.
CORRECT answer: 120
thank me the answer is x=3.6
Well, I would just reverse it. It seems you just have to reverse the whole problem.
-2(x + 3) = -2(x + 1) - 4
-2x - 6 = -2x - 2 - 4
0x = -6 + 6
0x = 0
x = unknown