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प्रश्न
Choose the correct choice in the following and justify:
11th term of the A.P. `-3, -1/2, 2,` ..., is ______.
विकल्प
28
22
–38
– 48`1/2`
उत्तर
11th term of the A.P. `-3, -1/2, 2,` ..., is 22.
Explanation:
Given that A.P. is -`3, -1/2, 2, ...`
First term a = -3
Common difference, d = a2 − a1 = `(-1/2) - (-3)`
= `(-1/2) + 3`
= `5/2`
We know that, an = a + (n − 1) d
a11 = `3 + (11 -1)(5/2)`
a11 = `3 + (10)(5/2)`
a11 = -3 + 25
a11 = 22
Hence, the answer is 22.
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