Answer: C) 20 Explanation: We know that, Total probability = 1 Given probability of black stones = 1/4 => Probability of blue and white stones = 1 - 1/4 = 3/4 But, given blue + white stones =  9 + 6 = 15 Hence, 3/4 ----- 15  1   -----  ? => 15 x 4/3 = 20.   Hence, total number of stones in the box = 20.

Answer: D) 135 Explanation: The given number series is 6, 6, 9, 18, 45, ? Here the series follows a pattern that, 6  6 x 1 = 6 6 x 1.5 = 9 9 x 2 = 18 18 x 2.5 = 45 45 x 3 = 135   Hence, the next number in the given number series is 135.

Answer: B) 60% Explanation: Here it is asked that 3 is what percent of 5 Let 3 is K percent of 5. => K x 5/100 = 3 => K = 300/5 = 60   Hence, 3 is 60% of 5.

Answer: A) i Explanation: We know that, i2 = -1i3 = i2 x i = -1 x i = -ii4 = i2 x i2 = -1 x -1 = 1Hence, i233  =i4 x 58 + 1 = i232 x i1 = 1 x i = i

Answer: C) 2:1 Explanation: Given rate of wheat at cheap = Rs. 2.90/kg Rate of wheat at cost = Rs. 3.20/kg Mixture rate = Rs. 3/kg Ratio of mixture =            2.90                              3.20                               3 (3.20 - 3 = 0.20)            (3 - 2.90 = 0.10)   0.20 : 0.10 = 2:1   Hence, wheat at Rs. 3.20/kg be mixed with wheat at Rs. 2.90/kg in the ratio of 2:1, so that the mixture be worth Rs. 3/kg.

Answer: C) 289 Explanation: Here the given number series is 270, 261, 279, 252, 289, 243 270 - 9 = 261 261 + 18 = 279 279 - 27 = 252 252 + 36 = 288 (not equals to 289) 288 - 45 = 243   Hence, the odd number in the given number series is 289.

Answer: A) 72 km Explanation: Rate of her upstream = 12/2.5 = 4.8 km/hr Then, ATQ Rate of downstream = 4.8 x 3 = 14.4 km/hr   Hence, the distance she covers downstream in 5 hrs = 14.4 x 5 = 72 kms.

Answer: A) 8, 72 yrs Explanation: Let the present ages be K,M Given K/M = 4/5 5K - 4M = 0 ......(1) Also given that, M - (K + 5) = 3 M - K = 8 .........(2) Then, by solving (1) & (2) M = 40 yrs and K = 32 yrs Hence, Total of ages = 40 + 32 = 72 yrs Difference of ages = 40 - 32 = 8 yrs.