Question

a=5, an=45, sn=400, then find its common difference

Answer 1

Answer:

8/3

Step-by-step explanation:

a = 5

an = 45

sn =400

We know that

Sn = n/2(a+an)

400=n/2(5+45)

400×2=n(50)

800=50n

800/50=n

n=16

an= a+(n-1)d

45=5+(16-1)d

45= 5+15d

45-5=15d

40=15d

40/15=d

d=8/3