The numbers of nuts stored by two squirrels, Burl and Shirl, at the beginning of September were in the ratio A : B. At the end of September, the numbers of nuts stored by Burl and Shirl were in the ratio C : D. If Burl had n times as many nuts at the end of September as at the beginning of September, then by what percent did the number of nuts stored by Shirl increase during September?

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\frac{100nAD}{(BC)}

\frac{100n(AD - B)}{(BC)}

\frac{100(D}{(BC)}*(n + A) - 1)

\frac{100D(n + A)}{(BC)}

100(\frac{nAD}{(BC)} - 1)

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Official Explanation

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Let's denote the percent change in Shirl's nuts as x.

Ratio at the beginning:

A : B

Ratio at the end:

An : B + \frac{Bx}{100}

C : D

\frac{An}{B + \frac{Bx}{100}} = \frac{C}{D}

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