CBSE NCERT Solutions Chapter 5 Arithmetic Progressions Exercise 5.2 Question 15
15. For what value of n, are the nth terms of two AP’s : 63, 65, 67 …. and 3, 10, 17, .. equal?
Solution:
Lets first consider AP 63, 65, 67 …..
First term = a = 63
Common difference = d = 65 – 63 = 2
Using formula
, to find nth term of arithmetic progression, we can say that
(1)
Now, consider second AP 3, 10, 17, ….
First term = a = 3
Common difference = d = 10 -3 = 7
Using formula
, to find nth term of arithmetic progression, we can say that
(2)
According to the given condition, we can write
(1) = (2)
Therefore, 13th terms of both the AP’s are equal.
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