Answer: D) 0 Explanation: As we know we have 10 letter and 10 different address and one more information given that exactly 9 letter will at the correct address....so the remaining one letter automatically reach to their correct address P(E) = favorable outcomes /total outcomesHere favorable outcomes are '0'.So probability is '0'.

Answer: C) 25 Explanation: a+b=5   ...(1)    and    3a+2b=20 ...(2)   Multiplying (1) by 2 and subtracting from (2), we get : a=10.   Putting a=10 in (1), we get : b=-5   Therefore,   (3a+b) = 3 x 10+(-5)=30-5=25.

Answer: D) 45 kg Explanation: Let the ratio of initial quantity of oils be 'x' => 4x, 5x & 8x.Let k be the quantity of third variety of oil in the final mixture.Let the ratio of initial quantity of oils be 'y'From given details,4x + 5 = 5y ..... (1)5x + 10 = 7y .....(2)8x + k = 9y ......(3) By solving (1) & (2), we getx = 5 & y = 5 From (3) => k = 5 Therefore, quantity of third variety of oil was 9y = 9(5) = 45kg.

Answer: D) 4 months Explanation: we can assume that Amar join into business after x months. So Amar money was invest into  (12 – x ) months.   76000×1257000×(12-x)=21   --> 912000 = 114000 ( 12 – x ) = 114 ( 12 – x ) = 912 --> x = 4 After 4 months amar join the business.

Answer: A) 277 Explanation: The given number series is    71      88       113       150       203          277    +17    +25       +37      +53        +74         +8      +12        +16       +21             +4          +4         +5   The series should be  71  88  112   150    203   276 i.e, the differences of the difference should be +4.   Hence, the odd man in the given series is 277.

Answer: B) 3/2 Explanation:  = log 33 + log 23+ log 103log10×3×22        =log33 12+log 23+log 10312log(10×3×22)                 =12log 33+3 log 2+12 log103log10+log3+log22                 =32log 3 + 2 log 2 + log 10log 3 + 2 log 2 + log 10 = 32

Answer: B) 2.7 hrs Explanation: Let Speed of boat in still water = b Let Speed of still water = w Then we know that, Speed of Upstream = U = boat - water Speed of Downstream = D = boat + water Given, U + D = 82 b - w + b + w = 82 2b = 82 => b = 41 kmph From the given data, 41 - w = 105/3 = 35 w = 6 kmph Now, b + w = 126/t => 41 + 6 = 126/t => t = 126/47  = 2.68 hrs.

Answer: D) 8 hrs 34 min Explanation: Number of pages typed by Adam in 1 hour = 36/6 = 6 Number of pages typed by Smith in 1 hour = 40/5 = 8Number of pages typed by both in 1 hour = (6 + 8) = 14Time taken by both to type 110 pages = (120 * 1/14) = 847 = 8 hrs 34 min.