19. If the numbers a, b, c, d, e form an A.P., then the value of a – 4b + 6c – 4d + e is (a) 0 (b) 1 (c) -1 (d) 2

Answer: a Explaination:Reason: Let x be the common difference of the given AP ∴ b = a + x, c = a + 2x, d = a + 3x and e = a + 4x ∴ a – 4b + 6c – 4d + e = a – 4 (a + x) + 6(a + 2x) – 4(a + 3x) + (a + 4x) = a – 4a – 4x + 6a + 12x – 4a – 12x + a + 4x = 8a – 8a + 16x – 16x = 0