Question

1,3,5.. ... is an arithmetic sequence. what is its 20th term​

Answer 1

Answer:

here 1st term is a= 1

common difference d=(3-1)=2

20th term=a+(n-1).d

=1+(20-1).2

=1+19.2

=1+38

=39

Answer 2

Solution :-

→ First term of given AP = a = 1

→ Common Difference = d = a2 - a1 = 3 - 1 = 2

So,

→ an = a + (n - 1)d

then,

→ a(20) = 1 + (20 - 1)2

→ a(20) = 1 + 19 * 2

→ a(20) = 1 + 38

→ a(20) = 39 (Ans.)

Hence, 20th term of given arithmetic sequence is equal to 39.

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