3 teaspoons = 1 tablespoon
4 tablespoons = 1/4 cup
According to the information above, how many teaspoons are equal to 3/8 cup?

A. 3
B. 4
C. 9
D. 12
E. 18
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\(3\,\,{\text{teaspoons}}\,\,\,\, \leftrightarrow \,\,\,\,1\,\,\,{\text{tablespoon}}\)

\(4\,\,{\text{tablespoons}}\,\,\,\, \leftrightarrow \,\,\,\,\frac{1}{4}\,\,\,{\text{cup}}\,\,\,\,\,\)

\(\frac{3}{8}cup\,\,\, = \,\,\,\,?\,\,\,{\text{teaspoons}}\)

\(\frac{3}{8}cup\,\,\,\left( {\frac{{4\,\,{\text{tablespoons}}}}{{\frac{1}{4}\,\,\,{\text{cup}}}}\,\,\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\,\,\,\left( {\frac{{3\,\,{\text{teaspoons}}}}{{1\,\,\,{\text{tablespoon}}}}\,\,\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\,\,\, = \,\,\,\frac{{3 \cdot 4 \cdot 4 \cdot 3}}{{8 \cdot 1}} = 18\,\,\,\,\,\,\,\,\,\left[ {{\text{teaspoons}}} \right]\)

This is a nice example of UNITS CONTROL technique, one of our most powerful tools!

(Arrows indicate licit converters.)

The above follows the notations and rationale taught in the GMATH method.
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3 x 4 = 12 teaspoons
12 teaspoons = ¼ cup, so it must be more than 12 so we choose E