Question: Tim buys a book of esoteric words. He learns 10 words from it a day. In 2 years the book has increased the number of words he knows by 50%. How many words did he know originally? Think carefully first, then make a decision:
In 2 years there are 365 * 2 = 730 days. So he has learned 730 * 10 = 7300 words. He knew 1 / .5 = 2 times that number of words before the book. So he knew 7300 * 2 = 14600 words before. So the answer is 14600.