Hi All,
We’re told that Terry originally planned to read 90 pages/day to complete a particular reading assignment. However, she was only able to read 75 pages/day at first (for a certain number of days), which left her 690 pages that had to be read in the last 6 days of that original timeframe. We’re asked for the TOTAL number of days needed to complete all of the reading.
The Arithmetic that this question is based on can be approached in a number of different ways – and you can actually use a ‘comparison’ to get to the final answer fairly quickly.
Since the original plan was to read 90 pages/day, the last 6 days of reading was supposed to be (6)(90) = 540 pages. Terry had to actually read 690 pages though – which is 690 – 540 = 150 more pages than she had originally planned to read during those final days.
The difference between the original rate (re: 90 pages/day) and the amount she actually read early-on (75 pages/day) is 90 – 75 = 15 pages/day. This is interesting since she needed to make up 150 pages at the end (and 150 is 10 times 15). This means that she was reading at that slower rate for the first 10 days of reading – and she had to make up the amount that she ‘fell behind’ during the final 6 days.
That’s 10 + 6 = 16 total days of reading.
Final Answer:
GMAT Assassins aren’t born, they’re made,
Rich