Bunuel
Rose walked along a track at an average speed of 100 meters per minute. Was the length of the track greater than half a kilometer? (1 kilometer = 1000 meters)
(1) She took less than 400 seconds to cover the track.
(2) She took more than 320 seconds to cover the track
Solution
Step 1: Analyse Question Stem
• Average speed is 100 meters per minute.
• Let us assume that the length of the track is d (in meters) and time taken to cover the track is t (in minutes).
• So, d = 100*t
o We need to find if d > 500 meters
o Or, \(100*t > 500\)
Step 2: Analyse Statements Independently (And eliminate options) – AD/BCE
Statement 1: She took less than 400 seconds to cover the track.
• According to this statement, \(t < (\frac{400}{60})\) minutes
• So, \(100*t < 100*\frac{20}{3}\)
o \(100*t < 666.66\)
o So, We cannot be sure if \(100*t > 500\), for example, it can 499 or 501.
Hence, statement 1 is not sufficient and we can eliminate answer options A and D
Statement 2: She took more than 320 seconds to cover the track
• According to this statement, \(t > (\frac{320}{60})\) minutes
• So, \(100*t > 100*\frac{16}{3}\)
o \(100*t > 533.33 ⟹ 100*t > 500\)
Hence, statement 2 is sufficient.
Thus, the correct answer is
Option B.