Since two numbers are greater than 21 and also their H.C.F. is 21 ∴ Two numbers are 21a and 21b, where a > 1, b > 1 and a, b are co-prime. Now, 21a×21b=3003×21 a×b=143 As, a and b are co-primes. So, a = 11 and b = 13 ∴ Sum of numbers =21(11+13) =21×24=504