X and Y are sets of positive integers. Is the greatest integer in X greater than the greatest integer in Y ?

(1) X is a set of 5 consecutive odd integers, each less than 20.
(2) Y is a set of 3 consecutive even integers, each less than 15.

In the rectangular coordinate system, are the points (r, s) and (u, v) equidistant from the origin?

(1) r + s = 1
(2) u = 1 - r and v = 1 - s.

What is the value of a⁴ - b⁴ ?

(1) a² - b² = 16
(2) a + b = 8

What is the ratio of p to r ?

(1) The ratio of p to 3r is 5 to 9.
(2) The sum of p and r is 16.

If ~$x+y\neq 0$~, what is the value of ~$\frac{ax+ay}{x+y}$~ ?

(1) x = 4 and y = 5.
(2) a = 6

Is the integer n a multiple of 15 ?

(1) n is a multiple of 20.
(2) n + 6 is a multiple of 3.

Do more than 50 percent of the children in a certain group have brown hair?

(1) 70 percent of the boys in the group have brown hair.
(2) 30 percent of the children in the group are girls with brown hair.

Is n divisible by 12 ?

(1) ~$\frac{n}{6}$~ is an integer.
(2) ~$\frac{n}{4}$~ is an integer.

Each of the offices in a certain building has a floor area of 200, 300, or 350 square feet. How many offices are on the first floor of the building?

(1) There is a total of 9,500 square feet of office floor space on the first floor of the building.
(2) Ten of the offices on the first floor have floor areas of 350 square feet each.

How much time did it take a certain car to travel 400 kilometers?

(1) The car traveled the first 200 kilometers in 2.5 hours.
(2) If the car's average speed had been 20 kilometers per hour greater than it was, it would have traveled the 400 kilometers in 1 hour less time than it did.