Number System On multiplying a number by 7, the product is a number each of whose digits is 3. The smallest such number is: 47649 48619 47719 47619 47649 48619 47719 47619 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP By hit and trail, we find that47619 * 7 = 333333.7) 333333 (47619 333333---------------- 0
Number System Sum of the digits number is 8 and their product is 12. Find the difference between the digits? None 4 6 2 None 4 6 2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP x + y = 8xy = 12(x – y)2 = (x + y)2 – 4xy (x – y)2 = 64 – 48 => (x – y) = 4
Number System 84 * 29 + 365 = ? 2801 - 2801 - 2071 2436 2801 - 2801 - 2071 2436 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP - 84 * (30 - 1) + 365= - (84 * 30) + 84 + 365= - 2520 + 449 = - 2071
Number System What number should come in the place of (?) in the following number series ? 1, 4, 9, 25, 49, ?, 169, 289, 361 11 321 225 121 11 321 225 121 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The series is (Prime No.)²So it is (11)² = 121
Number System What is the least number that should be added to 5200 to make it a perfect square ? 225 129 288 275 225 129 288 275 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP We sec (73)² = 5329 and (72)² = 5184ie 5329 > 5200 > 5184So 129 should be added to make is perfect square.
Number System An urn contains 9 blue, 7 white and 4 black balls. If 2 balls are drawn at random, then what is the probability that only one ball is white ? 92/190 89/190 90/190 91/190 92/190 89/190 90/190 91/190 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Total possible outcomes = 20C2 = 20 x 19/1 x 2 = 190Total favourable outcomes = 7C1 x 13C1 = 7 x 13 = 91∴ Required probability = 91/190
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