A train 280 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 22 sec
(B) 16 sec
(C) 17 sec
(D) 88 sec
(E) 12 sec
Answer and stream of consciousness: (B)
Stream of consciousness: Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 280 * 2/35 = 16 sec

Two pipes A and B can fill a tank in 36 hours and 45 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank?
Options:
(A) 20 hrs
(B) 22 hrs
(C) 23 hrs
(D) 24 hrs
(E) 21 hrs
Answer and stream of consciousness: (A)
Stream of consciousness: 1/( 1/36 +1/45) = 180/9 = 20 hrs

Find the number of zeroes in the expression 15*32*25*22*40*75*98*112*125
Options:
(A) 9
(B) 8
(C) 7
(D) 6
(E) 5
Answer and stream of consciousness: (A)
Stream of consciousness: Maximum power of 5 in the above expression can be calculated like this. Count all the powers of 5 in the above expression. So number of zeroes are 9.

95 white and black tiles will be used to form a 10x10 square pattern. If there must be at least one black tile in every row and at least one white tile in every column, what is the maximum difference between the number of black and white tiles that can be used?
Options:
(A) 75
(B) 80
(C) 85
(D) 90
(E) 95
Answer and stream of consciousness:
(C)
Stream of consciousness: Answer = C
Please refer diagram below
95 - 10 = 85