The fifth term of an arithmetic progression is 18 and the ninth term is 30. What is the first term of the progression?

✓ Correct Answer: Option B

Let the first term be a and the common difference be d. The 5th term is a + 4d = 18. The 9th term is a + 8d = 30. Subtracting the first equation from the second gives 4d = 12, so d = 3. Substitute d=3 into a + 4d = 18: a + 4(3) = 18 => a + 12 = 18 => a = 6.