Number System An urn contains 9 blue, 7 white and 4 black balls. If 2 balls are drawn at random, then what is the probability that only one ball is white ? 92/190 90/190 89/190 91/190 92/190 90/190 89/190 91/190 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Total possible outcomes = 20C2 = 20 x 19/1 x 2 = 190Total favourable outcomes = 7C1 x 13C1 = 7 x 13 = 91∴ Required probability = 91/190
Number System What is the value of ? in the following equations ? 72/? = ?/50 100 60 80 40 100 60 80 40 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (?)² = 72 x 50= (6 x 6 x 2) x (5 x 5 x 2)= (6 x 5 x 2)² = (60)²∴ ? = 60
Number System In a fraction, twice the numerator is two more than the denominator. If 3 is added to the numerator and the denominator each, then the resultant fraction will be 2/3 .What was the original fraction 17/12 19/12 7/12 11/12 17/12 19/12 7/12 11/12 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 7/12
Number System What is the sum of all the prime numbers from 20 to 40? 119 117 120 118 119 117 120 118 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 23 + 29 + 31 + 37 = 120
Number System 7.8% of 12.5 + 2.5% of 161 = ? 12 9 2 5 12 9 2 5 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 7.8 x 12.5/100 + 2.5 x 161/100= 0.975 + 4.025= 5
Number System What is the difference between the largest number and the least number written with the figures 3, 4, 7, 0, 3? 43893 70983 43883 43983 43893 70983 43883 43983 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 74330 Largest30347 Smallest-------------43983
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