1. Problem: Find the next number in the series 50, 40, 31, 24, 18, ... 2. Observe the differences between consecutive terms: $$40 - 50 = -10$$ $$31 - 40 = -9$$ $$24 - 31 = -7$$ $$18 - 24 = -6$$ 3. The differences are: -10, -9, -7, -6. They do not form a simple arithmetic progression, but let's check if the pattern is alternating or has a rule. 4. Another approach is to look at the differences of the differences: $$-9 - (-10) = 1$$ $$-7 - (-9) = 2$$ $$-6 - (-7) = 1$$ 5. The second differences are 1, 2, 1, which suggests a pattern alternating between 1 and 2. 6. If the pattern continues, the next second difference should be 2, so the next first difference is: $$-6 + 2 = -4$$ 7. Therefore, the next term is: $$18 + (-4) = 14$$ Answer: 14 (Option B)