BTGmoderatorLU wrote:Source: Magoosh

If Machine X can make 40 widgets in 8 minutes, how many widgets can it make in 1 hour?

A. 90
B. 180
C. 240
D. 300
E. 320

Let´s use UNITS CONTROL, one of the most powerful tools of our method!

\[? = 1{\text{h}}\,\,\left( {\frac{{60\,\,\min }}{{1\,{\text{h}}}}\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\,\left( {\frac{{40\,\,{\text{widgets}}}}{{8\,\,{\text{min}}}}\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\, = \,\,\,\underleftrightarrow {\frac{{60 \cdot 40}}{8}} = 300\,\,\,\left[ {{\text{widgets}}} \right]\]
Obs.: arrows indicate licit converters.


This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.

8 mins ~ 40 widgets
Divide by 8 both the sides:
1 min ~ 5 widgets
Multiply by 60 both the sides:
60 min ~ 300 widgets

Hence, machine will produce 300 widgets per hour.