# Tag Info

Accepted

### Easy way to convert from one fiat to another without using a calculator

First you have to understand the quote you are given. If you are told the conversion is $1.6$ to $1$, is that $1.6$ of $A$ is the same as $1$ of $B$ or the other way around? That tells you whether ...
• 364k

### Easy way to convert from one fiat to another without using a calculator

I'm trying to convert from one fiat to another without using a calculator. In my case, I was trying to convert 25 TRY to BGN. Let's assume that the daily rate for 1 BGN is 13 TRY. That means 25 * 0.13 ...
1 vote

### Prove $2^n + 2^m ≠ 2^p$

You might enjoy this view of the question, which provides an alternative proof. Writing $2^m$ in binary, we have a $1$ followed by $m$ $0$'s. For example: $2^1: 10 \\ 2^5: 100000$ How can we add two ...
• 30.2k
Accepted

### How can multiplication by 0 be defined as a many to one mapping to, or compactification of a point at, origin.

As I understand it the plan comes in two versions, which are the same except for when we do this or that. One version, as far as I can make out, is this: The Plan: Start with the line, $\Bbb R$. ...
• 85.5k

### Finding sum borrowed when two unequal annual instalments are given

We need the equality of the present value of the borrowed money $C_0$ and the present value of the two installments $I_1$ and $I_2$. I assume that the first installment is paid at the end of the first ...
• 28.3k
1 vote
Accepted

### Find $n$ given average distance between $0 \le a \le n-1$ and $1 \le b \le n-1$

I will start with a few points aimed at the original poster, which they may find useful for the future; the actual problem at hand is going to be dealt with at the very end. The original problem we ...
• 10.4k
1 vote

### How to "model" $\frac{6}{x-9}$

You have to drive $6$ km, but you forgot to change the car's summer tires to winter tires, so you have to drive $9$ km per hour slower than usual as a safety precaution. How long will it take you to ...
1 vote

### How to "model" $\frac{6}{x-9}$

There are $x$ people in a life boat. There are $6$ gallons of drinking water in the boat. $9$ of the people get swept off the boat by a big wave and drown (sorry about that). How much drinking water ...
• 38.3k
Accepted

### Fraction substraction arithmetic

First, expanding the fractions $\left(3+\frac{3}{8}\right)-\frac{5}{6}-\left(1+\frac{2}{3}\right) = \frac{24+3}{8}-\frac{5}{6}-\frac{3+2}{3}=\frac{27}{8}-\frac{5}{6}-\frac{5}{3}$ Next, finding a ...
• 52

### Is it possible to calculate the arithmetic mean from the geometric mean?

Since you want a estmated relationship between AM and GM, and there's no further constraint on the data, I can present a widely used formula for approximation in finance. Hope this will light you up a ...

### How get the cost price?

One way is $C=46200-B$. I am sure that is not what you are looking for, but it gets all the right numbers. Added: with your addition that you want to understand $$X+3\%=24200$$ that should really be ...
• 364k

### Show that $a^3+5a$ is an integer

From the Binomial Theirem: $(u+v)^3=u^3+3u^2v+3uv^2+v^3=(u^3+v^3)+3uv(u+v).$ So with $u=\sqrt[3]{1+\sqrt{\dfrac{152}{27}}}$ $v=\sqrt[3]{1-\sqrt{\dfrac{152}{27}}}$ (where in the expression for $v$ we ...
• 30.4k