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A book costs $1 plus half its price. How much does it cost?

Your answer:

  • $0.50

  • $1

  • $1.50

  • $2

  • $3

  • Other (please respond)


Results are only viewable after voting.
figured it out btw
the initial term is 1, and the rate of change is 1/2
so we can plug it into the geometric series formula (a1/1-r)
which then puts it at 1/(1-1/2)
which is simplified to 2
the answer is 2 guys. we can pack it up now.
 
As a pure math problem, with p = price:
$1 + p/2 = p
$1 + p/2 - p/2 = p - p/2
$1 = p/2
p/2 = $1
p = $2

As a question about sales and it being one dollar more than half price: That requires information not given, so it's unanswerable.
well technically it infinitely approaches 2 but at some point (assuming this is done on a regular cash register) it's going to round up to 2 once the price reaches 1.995$
Not quite how infinite values (or 1/value) works.
1/3 = 0.3333...
2/3 = 0.6666...
3/3 = 0.9999...
But 3/3 = 1/1 = 1, so 3/3 = 1 and 3/3 = 0.9999...
Thus, 0.9999... = 1

The basic algebra and the infinite sum are interchangeable. Frankly, computing it as an infinite sum is a waste of knowledge of infinity.
 
I don't get how it would approach 2 cuz 1 +.50 is 1.50, half of 1.50 is .75 and .75+1.50 =2.25.
it approaches 2 if you apply "a dollar plus half its price" on every iteration. so you have 1 + 0.5 = 1.5, 1 + 0.75 = 1.75, 1 + 0.875 = 1.875, 1 + 0.9375, etc etc.; just eyeballing it you can see the equation progresses as 2 - 1/2, 2 - 1/4, 2 - 1/8, 2 - 1/16, and so on until the fraction approaches zero and thus the sum approaches 2. solving it algebraically (assuming price and cost mean the same in this context) also gives x = 2 as solved early in the thread.
 
I don't get how it would approach 2 cuz 1 +.50 is 1.50, half of 1.50 is .75 and .75+1.50 =2.25.
the price is a constant 1$ plus half of its final price. You're adding the new iteration to the initial cost of 1$, not the value you had just solved for.

Here's a third way to think of it. The price of the book (x) can be put into the formula x=1+1/2(x).
Simplify this down to x=1+x/2
Then turn 1 into 2/2 and simplify to x=(2+x)/2
From there the equation can be simplified to 2x=x+2
Subtract x from both sides to get x=2

It's a bit drawn out but it should explain the much simpler method compared to my geometric sequence method earlier and Tea Guzzler's non-algebraic method.
 
This question is exactly one word away from being sensible/reasonable/objective, but in the absence of that word it is entirely moronic/unreasonable/subjective
The best way to word the problem would be "the price of the book is 1$ plus half of its final price" but the general consensus is that it's equal to 2. Not sure who voted 1.5 ngl
 
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