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: 18 42 24 81 18 42 24 81 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.
Number System A basket contains 5 blue, 4 green and 3 red ball. If three balls are picked at random, what is the probability that at least one is red ? 37/52 32/51 34/55 31/58 37/52 32/51 34/55 31/58 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Probability of having no red ball is9C3 / 12C3 = 21/55Probability of having at least one red ball is 1 - 21/55 = 34/55
Number System A number is doubled and 9 is added. If the resultant is trebled, it becomes 75. What is that number? 3.5 8 None of these 6 3.5 8 None of these 6 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x. Then,3(2x + 9) = 752x = 16 => x = 8
Number System What is the sum of 1 + 2 + 3+ ... + 27 ? 378 382 396 343 378 382 396 343 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Sum = 27 x (27 + 1)/2= 27 x 28/2= 27 x 14= 378
Number System The simplest form of 1.5 : 2.5 is : 17 : 19 13 : 11 3 : 5 5 : 7 17 : 19 13 : 11 3 : 5 5 : 7 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 3 : 5
Number System The sum of two numbers is 25 and their difference is 13. Find their product. 315 114 325 104 315 114 325 104 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be x and y. Then x + y = 25 and x - y = 13.x = 19; y = 6xy = 19 * 6 = 114
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