Question

The 11 th term and 21 st term of ap are 19 and 34 find 12th term of an ap
anewer plz fast​

Answer 1

Answer:

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Step-by-step explanation:

Given, t11=19 and t21 =34

We know that, tn = a+(n−1)d

∴ t11 = a+(11−1)d and t21 = a+(21−1)d

∴19 = a+10d...(i) and 34 = a+20d...(ii)

Subtracting equation (i) from (ii), we get

10d = 15

⇒d=1.5

Putting the value of d in equation (i), we get

19 = a+10(1.5)

19-15 = a

⇒a=4

Now, t12=3+(12−1)(1.5)

t12=3+16.5

t12=19.5

Answer 2

Step-by-step explanation:

d is 1.5 So 12th term is 20.5

The up answer has done a silly mistake. He wrote the value of a as 3 in equation and so the answer is wrong.

Correct answer is 20.5

Please rectify