40.8k views
5 votes
For positive integers $a$, $b$, and $c$, what is the value of the product $abc$? \[ \dfrac {1}{a + \dfrac {1}{b + \dfrac {1}{c}}} = \dfrac38 \]

User Vskubriev
by
5.8k points

2 Answers

2 votes

Answer:

4

Explanation:

User Yanina
by
6.5k points
1 vote

I don't think the $ signs work as math delimiters. I would be nice if they did.

That looks like a simple continued fraction ("simple" is a technical term meaning the numerators are all 1).


\frac{1}{a + \frac {1}{b + \frac {1}{c}}} = \frac 3 8

I could go on for hours about continued fractions. The way we expand a regular fraction as a continued fraction is essentially Euclid's algorithm for the GCD:


(3)/(8) = (1)/(\frac 8 3) = (1)/(2 + \frac 2 3) = (1)/(2 + (1)/(\frac 3 2)) = (1)/(2 + (1)/(1 + \frac 1 2))

So we have a=2, b=1, c=2, a product

abc=4

User Lane Aasen
by
6.4k points