Number System Pick the wrong number from the given number series. 3,4,10,33,135,685,4116 135 33 10 685 135 33 10 685 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The correct number is 136.3 x 1 + 1 = 44 x 2 + 2 = 1010 x 3 + 3 = 3333 x 4 + 4 = 136136 x 5 + 5 = 685685 x 6 + 6 = 4116
Number System The product of two natural numbers is 17. Then, the sum of the reciprocals of their squares is: 1/289 289 290/289 289/290 1/289 289 290/289 289/290 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be a and b. Then,ab = 17, a = 1 and b = 17So, 1/a2 + 1/b2 = (a2 + b2)/a2 b2 = (12 + 172)/(1 * 17)2 = 290/289
Number System A basket contains eight white and ten black balls. Two draws of one ball each are made without replacement. What is the probability that one ball is white and the other ball is black ? 80/153 80/151 80/152 80/150 80/153 80/151 80/152 80/150 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Two balls can be drawn from 18 balls in 18C2 Ways, ie 153 ways. One white from 8 white balls can be drawn in 8C1 = 8 ways and one black ball from 10 black can be drawn in 10C1 = 10 ways.∴ n(S) = 153, n(E) = 8 x 10 = 80∴ P(E) = 80/153
Number System The product of two consecutive position odd numbers is 6723. What is the smaller number? 71 83 79 74 71 83 79 74 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP n x (n + 2) = 6723= n² + 2n - 6723 = 0= n² + 83n - 81n - 6723 = 0= n(n + 83) - 81 (n + 83) = 0Therefore, (n - 81) (n + 83) = 0Therefore, n = 81, n + 2 = 83
Number System What is the sum of all the composite numbers up to 20? 132 130 128 131 132 130 128 131 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 = 132
Number System Find the greatest number which leaves the same remainder when it divides 25, 57 and 105. 12 8 16 18 12 8 16 18 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 105 - 57 = 4857 - 25 = 32105 - 25 = 80The H.C.F of 32, 48 and 80 is 16.
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