Required numbers are 10, 15, 20, 25, ..., 95 This is an A.P. in which a = 10, d = 5 and l = 95. tn = 95       a + (n - 1)d = 95 10 + (n - 1) x 5 = 95 (n - 1) x 5 = 85 (n - 1) = 17 n = 18 Requuired Sum = n (a + l) = 18 x (10 + 95)   = (9 x 105)   = 945. 2 2