Question

(vii) given a = 8,An = 62, Sn= 210, find n and d.​

Answer 1

Answer:

n = 6 and d = 10.8

step by step

since,An = a + (n-1)d

and Sn= n/2(A+An)

=210 = n/2(8+62)

n=420/70=6

and An = a+(n-1)d

62=8+(6-1)d

62=8+5d

54=5d

d=54/5=10.8

hence the value of n is 6 and d is 10.8