The 3rd and 7th terms of an arithmetic progression are 10 and 26 respectively. Find the first term.

Let the first term be a and common difference d. From a + 2d = 10 and a + 6d = 26, subtracting gives 4d = 16, so d = 4. Substituting: a + 2(4) = 10, giving a = 10 - 8 = 2. Option A (4) is a common error from subtracting incorrectly, and option C results from using wrong term positions.