Questions & Answers

Question

Answers

A.8:9

B.4:9

C.9:8

D.7:8

Answer

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Hint: Here, by the use of ratio concepts we will find the sub-duplicate ratio.

Let us consider the given ratio 81:64 be a: b, where $a = 81$ and $b = 64$. As, we know that if the ratio is given in the form of a: b then the sub-duplicate ratio can be written as $\sqrt a :\sqrt b $ .Therefore,

$ \Rightarrow \sqrt {81} :\sqrt {64} = 9:8$

Hence, the sub-duplicate ratio of 81:64 is 9:8.

Hence, the correct option for the given question is ‘C’.

Note: The sub-duplicate ratio of a: b is $\sqrt a :\sqrt b $ , whereas the duplicate ratio of a: b is ${a^2}:{b^2}$.

Let us consider the given ratio 81:64 be a: b, where $a = 81$ and $b = 64$. As, we know that if the ratio is given in the form of a: b then the sub-duplicate ratio can be written as $\sqrt a :\sqrt b $ .Therefore,

$ \Rightarrow \sqrt {81} :\sqrt {64} = 9:8$

Hence, the sub-duplicate ratio of 81:64 is 9:8.

Hence, the correct option for the given question is ‘C’.

Note: The sub-duplicate ratio of a: b is $\sqrt a :\sqrt b $ , whereas the duplicate ratio of a: b is ${a^2}:{b^2}$.