Step 1: Represent the total number of jewels. Let the total number of jewels be N. According to the problem:
Jewels in the first box = $\frac{1}{3}$N, Jewels in the second box = $\frac{k}{5}$N, Jewels in the third box = 66.
The total number of jewels is:
N = $\frac{1}{3}$N + $\frac{k}{5}$N + 66.
Step 2: Simplify the equation. Rearrange terms:
N − $\frac{1}{3}$N − $\frac{k}{5}$N = 66.
Combine terms:
$\left( 1 - \frac{1}{3} - \frac{k}{5} \right)$N = 66.
Simplify the coefficients:
$\left( \frac{3}{3} - \frac{1}{3} - \frac{k}{5} \right)$N = 66 = =\(>\) $\left( \frac{2}{3} - \frac{k}{5} \right)$N = 66.
Step 3: Solve for k. Since k is a positive integer, test values such that $\frac{2}{3} - \frac{k}{5} \(>\) 0$. Let k = 2:
$\frac{2}{3} - \frac{2}{5} = \frac{10}{15} - \frac{6}{15} = \frac{4}{15}$
Substitute into the equation:
$\frac{4}{15}$N = 66 = =\(>\) N = $\frac{66 \times 15}{4}$ = 990 jewels.
Answer: 990