Question

If the thickness of a pile of 12 cardboards is 35 mm, find the thickness of a pile of 294 cardboards.

Answer 1

Let x cm be the thickness of a pile of 294 cardboards.

Thickness (in cm)	3.5	x
Cardboard	12	294

\[\text{ Since the pile of the cardboards and its thickness are in direct variation, we have: }  \]
\[\frac{3 . 5}{x} = \frac{12}{294}\]
\[ \Rightarrow 3 . 5 \times 294 = x \times 12\]
\[ \Rightarrow x = \frac{3 . 5 \times 294}{12}\]
\[ = \frac{1029}{12}\]
\[ = 85 . 75 cm\]
\[\text{ Thus, the thickness of a pile of 294 cardboards will be 85 . 75 cm (or 857 . 5 mm) } . \]