Consider T as total time taken to record 420 page book. Average time 90 secs = 1.5 mins.
So question asks is total time T < 420*1.5 i.e. T<630?
1) Each tape was at most 40 minutesINSUFFICIENT
: We dont know how many tapes were recorded
2) The book was recorded on 15 tapesINSUFFICIENT
: We dont know how long each of those 15 takes took for recording
Combining (1) and (2) --We need to prove T<630
: Tape (out of 15 tapes) spent at the most 40
mins (i.e. less than or equal to 40
Maximum time that could have spent on recording = 15 * 40 = 600 (which is still less than 630)Hence choice(C) is the answer.
Tough 700+ Level RCs: Passage1 | Passage2 | Passage3 | Passage4 | Passage5 | Passage6 | Passage7
Reading Comprehension notes: Click here
PowerScore CR Bible - Official Guide 13 Questions Set Mapped: Click here