B = 5 + 53 + 55 + ... + 5101
52.B = 53 + 55 + 57 + .... + 5103
=> 52.B - B = (53 + 55 + 57 + ... + 5103) - (5 + 53 + 55 + ... + 5101)
24B = 5103 - 5
=> B =\(\frac{5^{103}-5}{24}\)
B= 5+53+55+...+5101
52 . B = 53 + 55 + 57 + ... + 5103
52 . B - B = ( 53 + 55 + 57 + ... + 5103 ) - ( 5+53+55+...+5101 )
24B = 5103 - 5
B = ( 5103 - 5 ) : 24