The numbers between 300 and 500 which are divisible by 7, are 301, 308, 315,....,497. This is an A.P with first of term = 301. Therefore from the nth term of A.P = a + (n - 1) d,we have, 497 = 301 + (n -1)7 ⇒196 = (n - 1)7 ⇒ n - 1 = 196/7 = 28 ⇒ Number of terms = n = 28 + 1 = 29 Now, sum =