Let the numbers are of the form abc. So, According to question, 100 a + 10b + c = 7K ....(i) 100c + 10b + a = 7m .....(ii) From, (i) – (ii) 99a – 99c = 7 (k–m) 99 (a – c) = 7n a – c = 7; a = 9, c = 2 a = 8, c = 1 Hence, 4 numbers, 259, 952, 168 and 861.