Question

Encuentre la suma de los 20 primeros múltiplos de 3 que sigue al 60

Answer 1

Fórmula:
Sn=n/2 [2a+(n-1)^r)]

Datos:
n=20
a=60
r=3

Sn=n/2 [2a+(n-1)^r)]
Sn= 20/2 [2 (60)+(20-1)^3]
Sn= 20 [60+(19)^3]
Sn=20 [60+6859]
Sn 20 [6919]
Sn= 138380

R= 138380

Answer 2

Fórmula:
Sn=n/2 [2a+(n-1)^r)]

Datos:
n=20
a=60
r=3

Sn=n/2 [2a+(n-1)^r)]
Sn= 20/2 [2 (60)+(20-1)^3]
Sn= 20 [60+(19)^3]
Sn=20 [60+6859]
Sn 20 [6919]
Sn= 138380

R= 138380