10/01/05 20:20:51
If Dave works alone he will take 20 more hours to complete a task
than if he worked with Diana to complete the task. If Diana works
alone, she will take 5 more hours to complete the complete the task,
then if she worked with Dave to complete the task? What is the ratio
of the time taken by Dave to that taken by Diana if each of them worked
alone to complete the task?
A. 4 : 1
B. 2 : 1
C. 10 : 1
D. 3 : 1
E. 1 : 2
What is the probability that a 3-digit positive integer picked at random will have one or more "7" in its digits?