Question : If $a + b = 10$ and $\sqrt{\frac{a}{b}}-13=-\sqrt{\frac{b}{a}}-11,$ then what is the value of $3ab+4a^{2}+5b^{2}?$
Option 1: $450$
Option 2: $300$
Option 3: $600$
Option 4: $750$
New: SSC CGL 2025 Tier-1 Result
Latest: SSC CGL complete guide
Suggested: Month-wise Current Affairs | Upcoming Government Exams
Correct Answer: $300$
Solution :
Given: $\sqrt{\frac{a}{b}}-13=-\sqrt{\frac{b}{a}}-11$
⇒ $\sqrt{\frac{a}{b}} +\sqrt{\frac{b}{a}} = -11 + 13 = 2$
Squaring both sides,
${\frac{a}{b}} +{\frac{b}{a}}+2 = 4$
⇒ ${\frac{a}{b}} +{\frac{b}{a}} = 2$
⇒ ${\frac{a}{b}} = 1$ and since $a+b=10$
So, $a=b=5$
So, $3ab + 4a^2 + 5b^2 = 3 × 25 + 4 × 25 + 5 × 25$
⇒ $3ab + 4a^2 + 5b^2 = 300$
Hence, the correct answer is $300$.
Related Questions
Know More about
Staff Selection Commission Combined Grad ...
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Get Updates BrochureYour Staff Selection Commission Combined Graduate Level Exam brochure has been successfully mailed to your registered email id “”.




