arslanama wrote:
A plane traveled k miles in its first 96 minutes of flight time. If it completed the remaining 300 miles of the trip in t minutes, what was its average speed, in
miles per hour, for the entire trip?
(A) 60 ( k + 300 )/(96 + t)
(B) kt + 96 ( 300 ) / 96t
(C) k + 300 / 60 ( 96 + y )
(D) (5k / 8) + (60(300) / t)
(E) (5k / 8) + 5t
Simple application of UNITS CONTROL, one of the most powerful tools of our method!
\(? = \frac{{\left[ {{\text{total}}\,\,\# \,\,{\text{miles}}} \right]}}{{\left[ {{\text{total}}\,\,\# \,\,\min } \right]}}\,\,\frac{{{\text{miles}}}}{{\min }}\,\,\,\left( {\frac{{60\,\,\min }}{{1\,\,\,{\text{h}}}}\,\,\begin{array}{*{20}{c}}\\
\nearrow \\ \\
\nearrow \\
\end{array}} \right)\,\,\, = \,\,60 \cdot \left( {\frac{{\left[ {{\text{total}}\,\,\# \,\,{\text{miles}}} \right]}}{{\left[ {{\text{total}}\,\,\# \,\,\min } \right]}}} \right)\,\,\,{\text{mph}}\,\,\,\)
(Arrows indicate licit converter.)
\(\left[ {{\text{total}}\,\,\# \,\,{\text{miles}}} \right] = k + 300\)
\(\left[ {{\text{total}}\,\,\# \,\,\min } \right]\,\,{\text{ = }}\,\,96 + t\)
\(? = \frac{{60\,\left( {k + 300} \right)}}{{96 + t}}\,\,\)
This solution follows the notations and rationale taught in the GMATH method.
Regards,
Fabio.
_________________
Fabio Skilnik :: GMATH method creator (Math for the GMAT)