Is x > 0 ?

(1) xy > 0
(2) x + y > 0

At a certain bakery, each roll costs r cents and each doughnut costs d cents. If Alfredo bought rolls and doughnuts at the bakery, how many cents did he pay for each roll?

(1) Alfredo paid $5.00 for 8 rolls and 6 doughnuts.
(2) Alfredo would have paid $10.00 if he had bought 16 rolls and 12 doughnuts.

If x and y are positive integers such that x = 8y + 12, what is the greatest common divisor of x and y ?

(1) x = 12u, where u is an integer.
(2) y = 12z, where z is an integer.

If n is an integer between 2 and 100 and if n is also the square of an integer, what is the value of n ?

(1) n is even.
(2) The cube root of n is an integer.

If n is an integer, is -3xⁿ positive?

(1) x is negative.

(2) n is odd.

Is |x| = y - z ?

(1) x + y = z
(2) x < 0

Over a certain time period, did the number of shares of stock in Ruth's portfolio increase?

(1) Over the time period, the ratio of the number of shares of stock to the total number of shares of stocks and bonds in Ruth's portfolio increased.
(2) Over the time period, the total number of shares of stocks and bonds in Ruth's portfolio increased.

A certain group of car dealerships agreed to donate x dollars to a Red Cross chapter for each car sold during a 30-day period. What was the total amount that was expected to be donated?

(1) A total of 500 cars were expected to be sold.
(2) 60 more cars were sold than expected, so that the total amount actually donated was $28,000.

If ~$x\neq -y$~, is ~$\frac{x-y}{x+y}> 1$~ ?

(1) x > 0
(2) y < 0

If n is a positive integer, is n³ - n divisible by 4 ?

(1) n = 2k + 1, where k is an integer.
(2) n² + n is divisible by 6.