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?
Stream of thoughts:
14600
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.

.

Thus, the answer is 14600