You can solve this math equation using your brain. Solve the puzzles and improve your logical thinking.
Puzzle:
1 + 5 = 18
2 + 7 = 27
3 + 9 = 36
5 + 10 = 45
4 + 20 = ?

Options:
A. 70
B. 72
C. 75
D. 68
Answer: B. 72
Solution:
1 + 5 = 6 * 3 = 18
2 + 7 = 9 * 3 = 27
3 + 9 = 12 * 3 = 36
5 + 10 = 15 * 3 = 45
4 + 20 = 24 * 3 = 72