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# Geometric Progressions watch

1. This is a dumb question, but idc.

In geometric investment type problems, what is the meaning of interest? also how do you calculate common ratio will be when given an interest percentage.

This question:
https://gyazo.com/ce01cfbe03619d817460aa4d760a63fd
2. You can think of it as a geometric progression of sorts, with A being the first term and the added interest being the "common ratio" (be aware that this is greater than 1 since interest adds to the initial investment)
3. (Original post by Naruke)
This is a dumb question, but idc.

In geometric investment type problems, what is the meaning of interest? also how do you calculate common ratio will be when given an interest percentage.

This question:
https://gyazo.com/ce01cfbe03619d817460aa4d760a63fd
Interest of 4%, for instance, means that after a year, in this case, could be different unit of time, that his cash increases by 4%, or if you prefer by a factor of 1.04 (what he already has is 100% then you add 4% which is 4/100 or 0.04)
4. (Original post by 13 1 20 8 42)
Interest of 4%, for instance, means that after a year, in this case, could be different unit of time, that his cash increases by 4%, or if you prefer by a factor of 1.04 (what he already has is 100% then you add 4% which is 4/100 or 0.04)
Hi, again! Could you tell me where I've gone wrong?

https://gyazo.com/0565b8741b3035479502fc8a518b2acd

multiplication factor would be 100 % - 15% = 85%

85 % = 0.85

5. (Original post by Naruke)
Hi, again! Could you tell me where I've gone wrong?

https://gyazo.com/0565b8741b3035479502fc8a518b2acd

multiplication factor would be 100 % - 15% = 85%

85 % = 0.85

What is the answer? Didn't sleep last night so a bit slow but nothing jumps out at first
6. (Original post by 13 1 20 8 42)
What is the answer? Didn't sleep last night so a bit slow but nothing jumps out at first
You and me both, I woke up yesterday at 3pm and haven't slept since

I think the part I'm getting wrong is using

solutionbank just uses n, do you know why this is?
7. (Original post by Naruke)
You and me both, I woke up yesterday at 3pm and haven't slept since

I think the part I'm getting wrong is using

solutionbank just uses n, do you know why this is?
I did think that might be erroneous, but then I thought I was missing something in thinking there was a problem..
but on closer inspection basically there's no need to use n-1; you see that after 7.88ish years the car will be at 5000, it seems you're going from year 1 instead of year 0 or something

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