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If the 5th and 12th terms of an A.P. are...

If the 5th and 12th terms of an A.P. are 30 and 65 respectively, what is the sum of first 20 terms?

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Verified by Experts

Given that,` a_5 = 30` and `a_12 = 65`
And, we know that `a_n = a + (n – 1)d`
So,` a_5 = a + (5 – 1)d`
`=> 30 = a + 4d `
...
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RD SHARMA-ARITHMETIC PROGRESSIONS-Solved Examples And Exercises
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  13. If a,b,c are in A.P., then show that (i) a^2(b+c), b^2(c+a), c^2(a+b) ...

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  14. If a, b, c are in A.P, then show that: b+c-a , c+a-b , a+b-c are in A....

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  16. If (b+c)/a,(c+a)/b,(a+b)/c are in A.P. show that 1/a,1/b1/c are als...

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