સમગુણોત્તર શ્રેણીના ત્રણ ક્રમિક પદોનો ગુણાકાર \(512\) છે. જો પહેલા અને બીજા પદમાં \(4\) ઉમેરવામાં આવે તો ત્રણેય સમાંતર શ્રેણીમાં થાય છે તો સમગુણોત્તર શ્રેણીમાં રહેલા ત્રણેય પદોનો સરવાળો મેળવો.

A \(36\)
B \(32\)
C \(24\)
D \(28\)

Verified Solution

Answer & Solution

Correct Answer

(D) \(28\)

Step-by-step Solution

Detailed explanation

Let the number be \(\frac{a}{r},a,ar\) Given \({a^3} = 512 \Rightarrow a = 8\) Now given \(\frac{8}{r} + 4,12,8r\) are in \(A.P.\) \( \Rightarrow 2{r^2} - 5r + 2 = 0\) \( \Rightarrow r = \frac{1}{2}\) Numbers are \(4,8,16,\) or \( 16,8,4,\) Sum of numbers \(=4+8+16=28\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From JEE Mains

Explore more questions on app