If p and n are positive integers and p > n, what is the remainder when p² - n² is divided by 15 ?

(1) The remainder when p + n is divided by 5 is 1.
(2) The remainder when p - n is divided by 3 is 1.

During an experiment, some water was removed from each of 6 water tanks. If the standard deviation of the volumes of water in the tanks at the beginning of the experiment was 10 gallons, what was the standard deviation of the volumes of water in the tanks at the end of the experiment?

(1) For each tank, 30 percent of the volume of water that was in the tank at the beginning of the experiment was removed during the experiment.
(2) The average (arithmetic mean) volume of water in the tanks at the end of the experiment was 63 gallons.

If ~$x=\frac{1}{2}$~ , is y equal to 1 ?

(1) ~$y^{2}\left ( x+\frac{1}{2} \right )=1$~
(2) ~$y(2x-1)=2x-y$~

Al, Pablo, and Marsha shared the driving on a 1,500 mile trip. Which of the three drove the greatest distance on the trip?

(1) Al drove 1 hour longer than Pablo but at an average rate of 5 miles per hour slower than Pablo.
(2) Marsha drove 9 hours and averaged 50 miles per hour.

At a refreshment stand, each can of soda sells for the same price and each sandwich sells for the same price. What is the total price for 2 sandwiches and 3 cans of soda at the stand?

(1) At the stand the total price for 1 sandwich and 1 can of soda is $3.
(2) At the stand the total price for 3 sandwiches and 2 cans of soda is $8.

Is w greater than 1 ?

(1) w + 2 > 0
(2) w² > 1

What is the value of 6x - 10 ?

(1) 3x - 5 = 16
(2) 12x - 10 = 74

Which of Company X and Company Y earned the greater gross profit last year?

(1) Last year the expenses of Company X were ~$\frac{5}{6}$~ of the expenses of Company Y.
(2) Last year the revenues of Company X were $6 million less than the revenues of Company Y.

What is the price for a certain meal listed on a menu?

(1) The total paid for the meal, sales tax, and gratuity is $10.84.
(2) The sales tax on food is 6 percent.

In a certain conference room each row of chairs has the same number of chairs, and the number of rows is 1 less than the number of chairs in a row. How many chairs are in a row?

(1) There is a total of 72 chairs.
(2) After 1 chair is removed from the last row, there is a total of 17 chairs in the last 2 rows.