Hi All,
We're told that C is the temperature in degrees Celsius and F is the temperature in degrees Fahrenheit, and the relationship between temperatures on the two scales is expressed by the equation 9C = 5(F - 32). On a day when the temperature extremes recorded at a certain weather station differed by 45 degrees on the Fahrenheit scale, we're asked by how many degrees did the temperature extremes differ on the Celsius scale. This question can be solved rather easily by TESTing VALUES (as Brent has shown in his post). In addition, the answer choices are sufficiently 'spread out' that we can use a little logic and a little math to answer this question without too much work.
The equation 9C = 5(F - 32) can be 'rewritten' as...
C = 5(F - 32)/9
5/9 is a little more than 1/2.... so we can 'rewrite' the equation again as....
C = (a little more than 1/2)(F - 32)
Thus, for every degree that F 'changes', the value of C will change by a little more than 1/2 of a degree.
In this question, F changes by 45 degrees, so the value of C will change by (a little more than 1/2)(45) degrees. Half of 45 is 22.5, so we're looking for an answer that's a little more than 22.5 degrees. There's only one answer that matches...
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
