Question

What would the sum of this arithmetic sequence be :
-6 + 3.5 + 13 + 22.5 + ... + 288.5.

Answer 1

Answer:

a= -6

d= 9.5

t= ?

n= ?

No.of terms

288.5= -6+(n-1)9.5

288.5+6 = 9.5n-9.5

294.5+9.5=9.5n

304=9.5n

n=304/9.5

n=32

Sum of nth terms

Sn= 32/2[2*-6+(32-1)9.5]

Sn=16[-12+294.5]

Sn=16*282.5

Sn=4520