How many hours did it take Helen to drive from her house to her parents' house?

(1) Helen's average speed on this trip was 72 kilometers per hour.
(2) If Helen's average speed on this trip had been 8 kilometers per hour greater, it would have taken her 1 hour less.

How many of the 42 people in a group are employed students?

(1) 29 of the 42 people are employed.
(2) 24 of the 42 people are students.

In the xy-plane, at what two points does the graph of y = (x + a)(x + b) intersect the x-axis?

(1) a + b = -1
(2) The graph intersects the y-axis at (0, -6).

Each person in a certain group supports only one of the two candidates R and T. Of the people in the group, 45 percent support Candidate R and the rest support Candidate T. How many people in the group are in favor of a flat tax?

(1) Of the people in the group who support Candidate R, 58 percent are in favor of a flat tax.
(2) Of the people in the group who support Candidate T, 22 are in favor of a flat tax.

John and Mary own shares of stock in a certain company. Does John own more shares of the company's stock than Mary?

(1) Mary owns more than 500 shares of the company's stock.
(2) The number of shares of the company's stock that John owns is 400 less than twice the number of shares of the company's stock that Mary owns.

Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?

(1) Machines X and Y, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does.
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does.

Beth's bank charges a service fee on a regular checking account for each month in which the balance on the account falls below $100 at any time during the month. Did the bank charge a service fee on Beth's regular checking account last month?

(1) During last month, a total of $1,000 was withdrawn from Beth's regular checking account.
(2) At the beginning of last month, Beth's regular checking account balance was $500.

For the students in class A, the range of their heights is r centimeters and the greatest height is g centimeters. For the students in class B, the range of their heights is s centimeters and the greatest height is h centimeters. Is the least height of the students in class A greater than the least height of the students in class B ?

(1) r < s
(2) g > h

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever?

(1) 880 children developed neither inflammation nor fever.
(2) 20 children developed fever.

If x is positive, is x > 3 ?

(1) (x - 1)² > 4
(2) (x - 2)² > 9