q: If the cost price of 50 articles is equal to the selling price of 15 articles, then the gain or loss percent is?
Options:
(A) 16
(B) 127
(C) 12
(D) 18
(E) 233
a: OK... Percentage of profit = 35/15 * 100 = 233%
The answer is (E).

q: In what time will a railway train 60 m long moving at the rate of 36 kmph pass a telegraph post on its way?
Options:
(A) 3
(B) 5
(C) 4
(D) 6
(E) 7
a: OK... T = 60/36 * 18/5 = 6 sec
The answer is (D).

q: A 21 cm long wire is to be cut into two pieces so that one piece will be 2/5th of the other, how many centimeters will the shorter piece be?
Options:
(A) 12
(B) 6
(C) 88
(D) 77
(E) 14
a:
OK... 1: 2/5 = 5: 2
2/7 * 21 = 6
The answer is (B).