Number System In how many ways can 5 boys be chosen from 6 boys and 4 girls so as to include exactly one girl ? 56 54 60 58 56 54 60 58 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP One girl can be chosen in 4C1 = 4 ways and 4 boys can be chosen in 6C4 = 15 ways ∴ Total number of ways = 4 x 15 = 60 ways.
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 ? 31/58 37/52 32/51 34/55 31/58 37/52 32/51 34/55 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 What is the sum of all the composite numbers up to 20? 130 132 131 128 130 132 131 128 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 = 132
Number System If the sum of one-half of a number exceeds one-third of that number by 7 1/3, the number is: 30 20 18 15 30 20 18 15 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x. Then,(1/2 x + 1/5 x) - 1/3 x = 22/311/30 x = 22/3x = 20
Number System Which number should replace question mark (?) in the following equation ? ?/342 = 38/? 114 118 116 112 114 118 116 112 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (?)² = 342 x 38Therefore, ? = √342 x 38 = √38 x 9 x 38 = 38 x 3 = 114
Number System Look at this series: 1000, 200, 40, ... What number should come next? 8 2 24 14 8 2 24 14 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP This is a simple division series. Each number is divided by 5. Rule = (1st number / 5 = 2nd number) (2nd number / 5 = 3rd number)....Now, (1000 / 5 = 200), (200 / 5 = 40), (40 / 5 = 8)...So answer is a = 8.
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