Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 2)
2.
| What should come in place of both x in the equation | x | = | 162 | . |
| 128 | x |
Answer: Option
Explanation:
| Let | x | = | 162 |
| 128 | x |
Then x2 = 128 x 162
= 64 x 2 x 18 x 9
= 82 x 62 x 32
= 8 x 6 x 3
= 144.
x = 144 = 12.
Discussion:
35 comments Page 4 of 4.
Onkar said:
5 years ago
X^2 = √(162*128).
= √20736.
X^2 = 144.
And X = 12.
= √20736.
X^2 = 144.
And X = 12.
(4)
K. Uma said:
5 years ago
X/√128=√162/X.
By cross multiplication,
X x X=√162 x √128,
X^2 = √162 x 128,
X^2 = √20736,
X^2 = √2^8 x 3^4,
X^2 = 2^4 x 3^2,
X^2 = 16 x 9.
X^2 = 144.
X = √144.
X= 12.
By cross multiplication,
X x X=√162 x √128,
X^2 = √162 x 128,
X^2 = √20736,
X^2 = √2^8 x 3^4,
X^2 = 2^4 x 3^2,
X^2 = 16 x 9.
X^2 = 144.
X = √144.
X= 12.
(4)
Deepak said:
3 years ago
The square roots are nothing but raised to 1/2. 128' and 162'.
So we can simply take that up and down respectively to make them squares of x.
Now, if we consider 12 and 14 from the options, their squares are 144 and 196 respectively, if we put both in place of x' and consider the ratios, we get that 144/128 and 162/144 and dividing these by 16 and 18 respectively we get the ratios to be equal i.e. 9:8.
But the ratios are not the same in the case of 196.
So, the answer is 12.
So we can simply take that up and down respectively to make them squares of x.
Now, if we consider 12 and 14 from the options, their squares are 144 and 196 respectively, if we put both in place of x' and consider the ratios, we get that 144/128 and 162/144 and dividing these by 16 and 18 respectively we get the ratios to be equal i.e. 9:8.
But the ratios are not the same in the case of 196.
So, the answer is 12.
(3)
Babirye Fazira said:
2 years ago
Well explained, Thanks all.
(8)
Sharana said:
1 year ago
Thanks all for explaining the answer.
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