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# help watch

1. (Original post by Zacken)
Use:
easy haha. i get it now, thanks
2. (Original post by Zacken)
Geometric series - does that help?
nope
3. (Original post by manuel132)
nope
Starts out half-full: first term = 1/2
common ratio = 1.01

Sum to n terms = 1, find n. Sorry, this is wrong. Not sum.
4. (Original post by Zacken)
Starts out half-full: first term = 1/2
common ratio = 1.01

Sum to n terms = 1, find n.
i'll be glad if you could elaborate yourself there because i don't get the picture
5. (Original post by Zacken)
Starts out half-full: first term = 1/2
common ratio = 1.01

Sum to n terms = 1, find n.
is the answer 70 weeks then?
6. (Original post by manuel132)
i'll be glad if you could elaborate yourself there because i don't get the picture
So the train starts out half full, that means we can say that the proportion of people on the train is 0.5. That's what we start off with.

Now in the next week( day?)/whatever time period, the amount increase by 1%, that's the same thing as multiplying by 0.5*1.01, that's the proportion of people in the second day/week/whatever.

Second time period/day/whatever: 0.5*1.01 * 1.01 again.

So we want to find n such that:
7. (Original post by manuel132)
is the answer 70 weeks then?
Almost!! 71 weeks.
8. (Original post by Zacken)
Almost!! 71 weeks.
thanks
9. (Original post by Zacken)
So the train starts out half full, that means we can say that the proportion of people on the train is 0.5. That's what we start off with.

Now in the next week( day?)/whatever time period, the amount increase by 1%, that's the same thing as multiplying by 0.5*1.01, that's the proportion of people in the second day/week/whatever.

Second time period/day/whatever: 0.5*1.01 * 1.01 again.

So we want to find n such that:
I'm unsure how we work out what n is. Because It's a power
10. (Original post by stopopups)
I'm unsure how we work out what n is. Because It's a power
Logarithms

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Updated: February 17, 2016
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