Question

how many terms should be added in the series 1+3+5+....to get sum 190​

Answer 1

Step-by-step explanation:

1+3+5=9

=>190-9=181

number =181

Answer 2

Step-by-step explanation:

for an arithmetic sequence.

∙an=a+(n−1)d.

∙Sn=n2[2a+(n−1)d]

where a is the first term and d the common difference.

we require to find d.

given a=21 then.

a20=21+19d=154.

19d=154−21=133⇒d=13319=7.