👤

S=10+20+30+40+50+...+1200

Răspuns :

20-10=10 dupaceia
(1200-10):10+1 calculezi si dupaia
[(1200+10)*cat ti-a dat mai sus]:2

(credema e asa)

10

10=10+0
20=10x2
10=10x0
20=10x2
30=10x3
.......

1200=10x120


120 termeni

2S=120X1200
S=60X1200=72000