If sushi rows 27 km upstream and 81 km down steam taking 9 hours each, then the speed of the stream
Options:
(A) 12 kmph
(B) 13 kmph
(C) 22 kmph
(D) 20 kmph
(E) 15 kmph

Speed upstream = 27/9 = 3 kmph
Speed down stream = 81/3 = 27 kmph
Speed of stream = (27-3) = 12 kmph So the answer is: (A).

How many positive integers less than 500 can be formed using the numbers 1,2,3,and 5 for digits, each digit being used only once.
Options:
(A) 22
(B) 34
(C) 73
(D) 26
(E) 11

Single digit numbers = 4
Double digit numbers = 4 x 3 = 12
Three digit numbers = 3 x 3 x 2 x 1 = 18
Total = 34 So the answer is: (B).

In g is a positive integer smaller than 200 and (14g)/60 is an integer, then g has how many different positive prime factors?
Options:
(A) 2
(B) 3
(C) 5
(D) 6
(E) 8

7g/30 tells us that g is a factor of 30, which has 2, 3, and 5 as its prime factors. Each of them is distinct. Moreover, all multiples of 30 less than 200 can be derived by multiplying these prime factors alone. Thus, number of different prime factors is 3. So the answer is: (B).

Adam sat with his friends in the Chinnaswamy stadium at Madurai to watch the 100 metres running race organized by the Asian athletics Association. Five rounds were run. After every round half the teams were eliminated. Finally, one team wins the game. How many teams participated in the race?
Options:
(A) 32
(B) 77
(C) 279
(D) 27
(E) 91
Total five rounds were run. So in the final round 2 teams must have participated. In the penultimate round 4 teams, and 3rd round 8, 2nd round 16 and in the first round 32 teams must have participated as in each round half of the teams got eliminated. So the answer is: (A).