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If 4 5 , a, 2 are three consecutive terms of an A.P., then find the value of a.

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Question

If `4/5` , a, 2 are three consecutive terms of an A.P., then find the value of a

Sum
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Solution

Here, we are given three consecutive terms of an A.P.

First term (a1) =  `4/5`

Second term (a2) = a 

Third term (a3) =  2  

We need to find the value of a. So, in an A.P. the difference of two adjacent terms is always constant. So, we get,

 d = a2 - a

d = a - `4/5`                      ................(1)

Also,

d = a3 - a2

d = 2 -a                        ...................(2) 

Now, on equating (1) and (2), we get,

`a - 4/5 = 2 - a`

` a + a = 2 +4/5`

      `2a = (10 + 4)/5`

        `a = 14/10`

          `a = 7/5`

Therefore,  `a = 7/5` 

 

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Chapter 5: Arithmetic Progressions - Exercise 5.7 [Page 56]

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R.D. Sharma Mathematics [English] Class 10
Chapter 5 Arithmetic Progressions
Exercise 5.7 | Q 14 | Page 56

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