q: Which of the following numbers is divisible by 12?
Options:
(A) 1332
(B) 1021
(C) 3221
(D) 4211
(E) 3233
a: OK... 1332. This is the only option with last two digits divisible by 12
The answer is (A).

q: If X is the sum of first 10 positive even integers and Y is the sum of first 10 positive odd integers, what is the value of x-y?
Please try to explain your answers
Options:
(A) 10
(B) 25
(C) 50
(D) 75
(E) 100
a: OK... First even minus first odd = 2-1 = 1;
The sum of first 2 even integers minus the sum of first 2 odd integers = (2+4)-(1+3) = 2;
The sum of first 3 even integers minus the sum of first 3 odd integers = (2+4+6)-(1+3+5) = 3;
We can see the patterns here, so the sum of first 10 positive even integers minus the sum of first 10 positive odd integers will be 10.
The answer is (A).

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).