An important question from ML Agarwal of Class10 (avichal publication)
The sum of the 5th and the 7th terms of an AP is 52 and the tenth term is 46. Find the AP.
ML Agarwal, Class10, Arithmetic Progression Chapter9, question no. 15
Rajan@2021Guru
The sum of the 5th and the 7th terms of an AP is 52 and the tenth term is 46. Find the AP.
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Given, sum of the 5th and 7th term is 52.
∴a+4d+a+6d=52⇒2a+10d=52⟶(1)
And, the 10th term is 46.
∴a+9d=46
multiplying it by 2 we get,
2a+18d=92⟶(2)
Solving equations (1) and (2) we get,
8d=40⇒d=5
Substituting the value of d in (1) we get,
2a+(10×5)=52⇒2a=52−50⇒a=1
Therefore, the required A.P. is,
1,6,11,16,21,26,31,.....