An important question from ML Agarwal (avichal publication) of class10 Find the 20th term of the AP whose 7th term is 24 less than its 11th term and first term is 12

ML Publication Class 10, Arithmetic Progression Chapter 9, question no.13

Rajan@2021Guru

# Find the 20th term of the AP whose 7th term is 24 less than its 11th term and first term is 12

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## Given ,

First termÂ =a=12

Let the common difference beÂ d

and we know 7th termÂ a7â€‹=a+6d

Â and 11th termÂ a11â€‹=a+10d

According to question ,

Â a11â€‹âˆ’a7â€‹=24

Â a+10dâˆ’(a+6d)=24

Â a+10dâˆ’aâˆ’6d=24

Â d=6

We know that,

20th termÂ =a20â€‹=a+19d=12+19(6)

=12+114

=126

So , the 20th term of AP is 126.