<p>Here's the problem:</p>

<p>If 4(Triangle)/6(Triangle) + 5/17 = 1, what digit does Triangle represent?</p>

<p>The book says its 8,here's the explanation:</p>

<p>If 4(Triangle)/6(Triangle) + 5/17 = 1, then 4(Triangle)/6(Triangle) = 12/17

since 12/17 + 5/17 = 1.</p>

<p>Since 4(Triangle)/6(Triangle) = 12/17, 4(Triangle) must be a multiple of 12.Hence, 4(Triangle) = 48, so Triangle = 8.</p>

<p>I tried plugging 8 into the triangles but, it doesn't equal 1.</p>