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 ? 91/190 90/190 89/190 92/190 91/190 90/190 89/190 92/190 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 ind the number, difference between number and its 3/5 is 50 123 124 120 125 123 124 120 125 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number = x,Then, x-(3/5)x = 50,=> (2/5)x = 50 => 2x = 50*5,=> x = 125
Number System A man engaged a servant on the condition that he would pay him Rs.710 and a uniform after a year service. He served only for 8 months and got Rs.460 and a uniform. Find the price of the uniform? Rs.20 Rs.30 Rs.25 Rs.40 Rs.20 Rs.30 Rs.25 Rs.40 ANSWER DOWNLOAD EXAMIANS APP
Number System 75% of 250 - ?% of 380 = 54.5 31 35 33 39 31 35 33 39 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 250 x 75/100 - 380 x ?/100 = 54.5= 250 x 75 - 380 x ?= 54.5 x 100= 18750 - 380 x ?= 5450= 380 x? = 18750 - 5450= 13300= ? = 13300/380 = 35
Number System Find the smallest number which should be multiplied with 520 to make it a perfect square. 120 None of these 30 55 120 None of these 30 55 ANSWER DOWNLOAD EXAMIANS APP
Number System If x + y = 61 and xy = 888, What is the value of x²+ y² ? 1945 1965 1955 1975 1945 1965 1955 1975 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Because (x + y)² = x² + y² + 2xy∴ x² + y² = (x + y)² - 2xy∴ x² + y² = (61)² - 2 x 888= 3721 - 1776 = 1945
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