ABC26GN3041 · Ratio and Proportion
Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:
The product of the duplicate ratio of $2 a: 6 b$ and the reciprocal ratio of $4 a^{2}: 25 b^{2}$ is
(a)0
(b)1
(c)$a: b$
(d)None of these
Answer
Explanation
Duplicate ratio of $2 a: 6 b=(2 a)^{2}:(6 b)^{2}$ $$=4 a^{2}: 36 b^{2}=a^{2}: 9 b^{2} .$$ Reciprocal ratio of $4 a^{2}: 25 b^{2}=\frac{1}{4 a^{2}}: \frac{1}{25 b^{2}}=25 b^{2}: 4 a^{2}$. $$\text { ∴ } \text { Required product }=\frac{a^{2}}{9 b^{2}} \times \frac{25 b^{2}}{4 a^{2}}=\frac{25}{36} \text {. }$$
Explanation as extracted from the printed page; notation may be imperfect.
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