Number System What is the sum of 1 + 2 + 3+ ... + 27 ? 343 378 396 382 343 378 396 382 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Sum = 27 x (27 + 1)/2= 27 x 28/2= 27 x 14= 378
Number System Thrice the square of a natural number decreased by 4 times the number is equal to 50 more than the number. The number is: 5 10 4 6 5 10 4 6 ANSWER DOWNLOAD EXAMIANS APP
Number System If (182)² is added to the square of a number, the answer so obtained is 47765. What is the number ? 101 121 111 131 101 121 111 131 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the no. be xTherefore x² + (182)² = 47765Therefore x² = 47765 - (182)2 = 47765 - 33124Therefore x² = 14641, Therefore x = 121
Number System What is the least number that should be added to 5200 to make it a perfect square ? 275 129 288 225 275 129 288 225 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 How many numbers up to 100 and 300 are divisible by 11? 18 20 22 21 18 20 22 21 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (300 – 100)/11 = 200/11 = 18 2/1118 Numbers
Number System A box contains 5 red, 4 black and 4 blue balls. If 3 balls are drawn randomly from the box, what is the probability that there are exactly 2 blue balls in the three drawn balls ? 27/143 28/144 29/145 30/146 27/143 28/144 29/145 30/146 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Total balls = 5 + 4 + 4 = 13∴ n(S) = 13C3 = 2862 blue balls can be selected from 4 balls in 4C2 = 6 ways and the remaining one ball is to be selected from 9 balls in 9C1 = 9 ways ∴ n(E) = 6 x 9∴ P(E) = 6 x 9/286 = 27/143
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