Question 1014351: Thr 20th term of an arithmetic progression is 10 and the 50th term is 70, find the first term and the common difference
Answer by ikleyn(52788) (Show Source): You can put this solution on YOUR website! .
Thr 20th term of an arithmetic progression is 10 and the 50th term is 70, find the first term and the common difference
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The formula for the n-th term of an Arithmetic progression is
= + (n-1)*d.
So,
= + 19*d, (1)
= + 49*d. (2)
Now, distract (1) from (2). You will get
70 - 10 = 30*d.
Find d from there.
Then think what to do next.