vinay911 wrote:
Q) Lines P, Q and R are parallel to each other.Is the slope of the line P positive?
(1) Line R passed through (6, 2).
(2) Line P and Q passes through (–6, 2) and (–6, –2) respectively.
when I saw that the stmt (2) gives us a line parallel to y-axis i marked B as sufficient. Doesnt such a line have 'infinite slope'. I was confused if this information is sufficient. Please advise.
In statement (2), the equation of the line is x = -6.
A line parallel to the Y-axis has no slope, "infinity" is not a specific number.
Think of a line with negative slope, passing through the point (-6, -2). Start tilting it until it will also pass through the point (-6, 2). All the time, the slope of the line has been negative, then, when reaching the point (-6, 2) ... it just "vanished" ... no slope.
Do the similar process, starting with a line with positive slope, passing through the point (-6, -2) and tilt it until it also passes through the point (-6, 2). Now, all the time, the slope has been positive, before it "disappeared"...
It seems like the slope could be any "infinitely" large positive number, or any "infinitely" small negative number. Maybe this could be a reason to answer E.
Anyway, it is weird to ask about something non-existent whether it is positive or negative.
I hope there are no such questions on a real test.