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11 grade maths others

The first term of an arithmetic sequence is equal to 200 and the common difference is equal to -10. Find the value of the 20th term.






Profile image of Aniket Singh
1 Year agoGrade
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1 Answer

Profile image of Askiitians Tutor Team
1 Year ago

To find the 20th term of an arithmetic sequence, we use the formula for the nth term of an arithmetic sequence:

a_n = a + (n - 1)d

where:

a is the first term of the sequence,
d is the common difference,
n is the term number, and
a_n is the nth term.
Here:

a = 200 (first term),
d = -10 (common difference),
n = 20 (we need to find the 20th term).
Substituting the values into the formula:

a_20 = 200 + (20 - 1)(-10)

Simplify the expression step by step:

Compute (20 - 1): a_20 = 200 + 19(-10)

Multiply 19 by -10: a_20 = 200 - 190

Subtract 190 from 200: a_20 = 10

Thus, the 20th term of the arithmetic sequence is 10.