Number System If a number is multiplied by. three-fourth of itself, the value thus obtained is 10800. What is that number ? 180 120 60 260 180 120 60 260 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x.∴ x x 3x/4 = 10800= x² = 10800 x 4/3 = 14400∴ x = √14400 = 120
Number System If the difference between a number and its three-fourth is 18, find the number. 72 57 68 61 72 57 68 61 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x.According to the question,x - 3x/4 = 18= x/4 = 18= x = 4 x 18 = 72
Number System Supply the missing figure : 1, 4, 9, 16, 25 .... 49 16 36 42 23 16 36 42 23 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 36
Number System Two numbers are in the ratio 3:5. If 9 be subtracted from each, they are in the ratio of 9:17. The first number is: 30 36 27 18 30 36 27 18 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (3x-9):(5x-9) = 9:17 x = 12 => 3x = 36
Number System If (47)² is added to the square of a number the answer thus obtained is 2290. What is the number ? 7 10 8 9 7 10 8 9 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the no. be x Therefore, x² + (47)² = 2290Therefore, x² = 2290 - 2209 = 81Therefore, x = 9
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 ? 30/146 27/143 29/145 28/144 30/146 27/143 29/145 28/144 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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