In this situation, why is it that we have to find the LCM of 3 secs and 10 secs?
Try simulating the problem.
How should I simulate the problem?
in 30 s 10 people alived themselves and 3 people unalived themselves. so in total the growth rate for in 30 s was (10-3) i.e 7. so clearly we want growth rate for 1 person
so growth rate of ppl seconds
7 30
1 x
find x by cross multiplying which will get you x=30/7
therefore answer is = option B
For example:
- a person is born in the 3rd, 6th, 9th …,
- a person dies in the 10th, 20th and 30th second etc…
Do you now see the relevance of 30 seconds?