Practicing Success
With reference to a number greater than one, the difference between itself and its reciprocal is 25% of the sum of itself and its reciprocal. By how much percent is the fourth power of the number greater than its square? |
57.8 62.5 64.5 66.7 |
66.7 |
Let the no. = x x - \(\frac{1}{×}\) = \(\frac{25}{100}\) (x + (\(\frac{1}{×}\)) x2 - 1 = \(\frac{1}{4}\) (x2 + 1 ) 4x2 - 4 = x2 + 1 3x2 = 5 ⇒ x2 = \(\frac{5}{3}\) & x4 = \(\frac{25}{9}\) Required percentage = \(\frac{\frac{25}{9} -\frac{5}{3}}{\frac{5}{3}}\) × 100 = 66.7% |