Number System The difference between a positive proper fraction and its reciprocal is 9/20. The fraction is: 3/5 4/5 3/10 5/4 3/5 4/5 3/10 5/4 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 1/x - x = 9/20 20x2 + 9x - 20 = 0 20x2 + 25x - 16x - 20 = 0 5x(4x + 5) -4(4x + 5) = 0(4x + 5)(5x - 4) = 0x = 4/5
Number System What least number shall be added to 4700 to make it a perfect square ? 61 71 91 81 61 71 91 81 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (69)² = 4761 and (68)² = 4624Clerly 4624 < 4700 < 4761So 61 should be added to make 4700 a perfect square.
Number System If the difference between a number and its three fifths is 62, what is the number ? 165 175 155 145 165 175 155 145 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x.∴ x - 3x/5 = 62or x = 62 x 5/2 = 155
Number System In a fraction, twice the numerator is two more than the denominator. If 3 is added to the numerator and the denominator each, then the resultant fraction will be 2/3 .What was the original fraction 17/12 19/12 11/12 7/12 17/12 19/12 11/12 7/12 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 7/12
Number System What should come in the place of ' ? ' in the following number series ? 2, 5, 9, 19, 37, ? 78 77 75 76 78 77 75 76 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 2 x 2 + 1 = 5;5 x 2 - 1 = 99 x 2 + 1 = 19: 19 x 2 - 1 = 3737 x 2 + 1 = 75
Number System A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is: 42 81 18 24 42 81 18 24 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the ten's and unit's digit be x and 8/x respectively. Then, (10x + 8/x) + 18 = 10 * 8/x + x 9x2 + 18x - 72 = 0 x2 + 2x - 8 = 0 (x + 4)(x - 2) = 0 x = 2 So, ten's digit = 2 and unit's digit = 4. Hence, required number = 24.
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