Question

S=22+25+28+....+301
S=?
ofer coroana+puncte

Answer 1

    
$Calculam ~numarul ~de~ termeni ~(n): \\ \\ n= \frac{301-22}{3} +1 =\frac{279}{3} +1 =93+1=94~termeni \\ \\ S= \frac{94(301+22)}{2}= \frac{94\;\cdot\;323}{2}=47\cdot 323= \boxed{15181}$

Answer 2

obsevam ca numerele sunt din 3 in 3 incepand cu 22 pana la 301
S=22+25+28+......+301=(301+22)x(numarul de termeni):2
numarul de termeni=(301-22):3+1=279:3+1=93+1=94 termeni
S=94x(301+22):2=94x323:2=30362:2=15181