Number System Radha's present age is three years less than twice her age 12 years ago. Also the respective ratio between Raj's present age and Radha's present age is 4 : 9. What will be Raj's age after 5 years ? 14 years 17 years 15 years 16 years 14 years 17 years 15 years 16 years ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let Radha's present age = x years.∴ x = 2 (x = 12) - 3= x = 2x - 24 - 3= x = 27∴ Raja's present age = 4/9 x 27= 12 years ∴ Raja's age after 5 years = 12 + 5 = 17 years
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 31/58 34/55 32/51 37/52 31/58 34/55 32/51 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 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 89/190 91/190 90/190 92/190 89/190 91/190 90/190 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 (√6 + 1)² = ? + 2√6 8 7 6 5 8 7 6 5 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? = (√6 + 1)² - 2√6= (√6)² + 2 x √6 + 1 + 1² - 2√6= 6 + 2√6 + 1 - 2√6 = 6 + 1 = 7
Number System Which one of the following is the sum of the numbers 1, 3, 5, 7, 9…. up to nth number? N2 N2 + 1 N(N + 1) N(N + 1)/2 N2 N2 + 1 N(N + 1) N(N + 1)/2 ANSWER DOWNLOAD EXAMIANS APP
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