Given the following reasoning and answer, what was the question? 1 minute is 60 seconds, so 4 minutes is 4 * 60 = 240 seconds. During this time there would be 240 / 20 = 12 big crashes. And also 240 / 10 = 24 car collisions. So in total during 4 minutes there would be 12 + 24 = 36 accidents.
 The answer: 36

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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The question Every 10 seconds, there is a car collision, and every 20 seconds there is a big crash. How many accidents overall will happen in 4 minutes?