I got this question on knewton test. It is very good question. Here's the question, that I want to share:
3 + 3 + 3 + 2 × 3^2 + 2 × 3^3 + 2 × 3^4 + 2 × 3^5 + 2 × 3^6 + 2 × 3^7 =???
[spoiler]
Answer is 3^8
Hint: Find the common terms 3+3+3 can be written as 3^2[/spoiler]
3 + 3 + 3 + 2 × 3^2 + 2 × 3^3 + 2 × 3^4 + 2 × 3^5 + 2 × 3^6 + 2 × 3^7 =???
[spoiler]
Answer is 3^8
Hint: Find the common terms 3+3+3 can be written as 3^2[/spoiler]
