Răspuns :
5 + 10 + 15 + ....+625 =
n = ( 625 - 5 ) : ( 10 - 5) +1 =
n = 620 : 5 +1
n = 124 + 1
n = 125
S = [( 625 +5) × 125 ] : 2 =
S = ( 630 × 125 ) : 2 =
S = 78750 : 2
S = 39375.
n = ( 625 - 5 ) : ( 10 - 5) +1 =
n = 620 : 5 +1
n = 124 + 1
n = 125
S = [( 625 +5) × 125 ] : 2 =
S = ( 630 × 125 ) : 2 =
S = 78750 : 2
S = 39375.