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This is a pretty simple question, I'm afraid I have been out of math-land for too long!

We have two currencies, the U.S. dollar and the rupee.

$1 us dollar = .015 rupees (just an example, probably no where near the actual conversion).

Let's say I have $100,000$ rupees, how do I figure out the new value of my rupees if the value raises to be equal to the U.S. dollar ($1 U.S. dollar = 1 rupee)

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If you have $r$ rupees, and each rupee is worth $x$ dollars, then you have $rx$ dollars. – Arturo Magidin Dec 3 '10 at 17:26
up vote 2 down vote accepted

Multiply the number of rupees by the value in dollars of one rupee.

If the problem is that your conversion "goes the other way" (that is, you have something like 1 US dollar = 0.75 rupees, then "solve" for how many dollars equals one rupee first: \begin{align*} 1\text{ dollars} &= 0.75\text{ rupees}\\ \frac{1}{0.75} \text{ dollars} &= \frac{0.75}{0.75} \text{ rupees}\\ \frac{4}{3}\text{ dollars} &= 1\text{ rupees.} \end{align*} and then you can just multiply the number of rupees by $\frac{4}{3}$ to get the number of dollars.

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thank you! i'd up-vote but no reputation yet... – Derek Adair Dec 3 '10 at 17:35

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