If each of the students in a certain mathematics class is either a junior or a senior, how many students are in the class?

(1)   If one student is to be chosen at random from the class to attend a conference, the probability that the student chosen will be a senior is 4/7.
(2)   There are 5 more seniors in the class than juniors.

If the average (arithmetic mean) of four different numbers is 30, how many of the numbers are greater than 30?

(1)   None of the four numbers is greater than 60.
(2)   Two of the four numbers are 9 and 10, respectively.

If ~$a, b, k$~, and ~$m$~ are positive integers, is ~$a^k $~a factor of ~$b^m$~?

(1)   ~$a$~ is a factor of ~$b$~.
(2)   ~$k ≤ m$~

If ~$b, c$~, and ~$d$~ are constants and ~$x^2 + bx + c = (x + d)^2$~ for all values of ~$x$~, what is the value of ~$c$~?

(1)   ~$d = 3$~
(2)   ~$b = 6$~

If every car sold last week at a certain used-car dealership was either a coupe or a sedan, what was the average (arithmetic mean) sale price for all the cars that were sold at the dealership last week?

(1)   The average sale price for the sedans that were sold at the dealership last week was $10,600.

(2)   The average sale price for the coupes that were sold at the dealership last week was $8,400.

In the xy-plane, line l and line k intersect at the point (16/5, 12/5).  What is the slope of line l?

(1)   The product of the slopes of line l and line k is –1.

(2)   Line k passes through the origin.

Professor Vásquez gave a quiz to two classes.  Was the range of scores for the first class equal to the range of scores for the second class?
(1)   In each class, the number of students taking the quiz was 26, and the lowest score in each class was 70.
(2)   In each class, the average (arithmetic mean) score on the quiz was 85.

If x/600 = y/300, is y equal to 1,000?

(1)   x + y = 3,000
(2)   3x = 6,000

Joanna bought only $0.15 stamps and $0.29 stamps.  How many $0.15 stamps did she buy?

(1)   She bought $4.40 worth of stamps.
(2)   She bought an equal number of $0.15 stamps and $0.29 stamps.

In the xy-plane, is the slope of line k positive?

(1)   Line k passes through the points (-1, -7) and (2, 5).
(2)   Line k has equation y = 4x – 3.