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 If the difference between a number and its three fifths is 62, what is the number ? 165 155 145 175 165 155 145 175 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x.∴ x - 3x/5 = 62or x = 62 x 5/2 = 155
Number System If the sum of the two numbers is 22 and the sum of their squares is 404, then the product of the numbers is: 40 88 80 44 40 88 80 44 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be x and y. Then, (x + y) = 22 and x2 + y2 = 404 Now, 2xy = (x + y)2 - (x2 + y2) 2xy= 222 - 404 = 484 - 404 = 80xy = 40
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 Sum of two numbers is 80. Greater number exceeds by 5 from four times of the smaller. Find the numbers? 62, 18 64, 16 65, 15 60, 20 62, 18 64, 16 65, 15 60, 20 ANSWER DOWNLOAD EXAMIANS APP
Number System In how many different ways can the letters of the word 'LEASE' be arranged ? 80 40 None of these 60 80 40 None of these 60 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The world LEASE consists of 5 letters in which E comes twice ∴ 51/21 = 5x4x3x2x1/2x1 = 60
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