Answer: C) 2/21 Explanation: Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.   Probability that both marbles are blue = ³C₂/¹⁵C₂ = (3 x 2)/(15 x 14) = 1/35 Probability that both are yellow = ²C₂/¹⁵C₂ = (2 x 1)/(15 x 14) = 1/105 Probability that one blue and other is yellow = (³C₁ x ²C₁)/¹⁵C₂ = (2 x 3 x 2)/(15 x 14) = 2/35   Required probability = 1/35 + 1/105 + 2/35 = 3/35 + 1/105 = 1/35(3 + 1/3) = 10/(3 x 35) = 2/21

Answer: A) -1/2 Explanation: Rewrite equation as 122x+1 = 120   Leads to 2x + 1 = 0    Solve for x : x = -1/2

Answer: B) 6 kmph Explanation: Speed of the stream = 1Motor boat speed in still water be = x kmphDown Stream = x + 1 kmphUp Stream = x - 1 kmph[35/(x + 1)] + [35/(x - 1)] = 12x = 6 kmph

Answer: B) 8 Explanation:     AmitBharatNo.of Days4540Efficiency2.22Percent(=145)2.5 Percent(=140)   Amit did the work in 56 days = 56×145×2=2845    Therefore, Rest work 17/45 was done by Amit and Bharath = 174517360 = 8 days       ( since Amit and Bharath  do the work in one day = 145+140=17360)

Answer: B) Rs. 420 Explanation: As given in the question, Marked price is 25% more than the Cost price. => C.P of the article = 34 x 400 = 300  Now,  Let the original S.P of the article be Rs. P Now the new S.P = P + 16.666 +13.333300 x P  => S.P = 7P6 According to the question, 7P6 - 300 = 2P - 300 => 5P = 1800 => P = Rs. 360 Hence, the increased S.P = 360 x 7/6 = Rs. 420.