itisSheldon wrote:
Is the slope of the line that passes through the point (p, q) positive?
1) p, q > 0
2) The x-intercept of the line is k, such that k > p.
(1) is simply not sufficient.
(2) So the line passes through the point (k,0). We have two points as (p,q) and (k,0) which lie on this line. Slope = (q-0)/(p-k) = q/(p-k)
Since k > p, p - k is negative but we dont know whether q is positive or negative. So we cannot say whether slope is positive or negative. Not sufficient.
Combining, q is positive and p - k is negative. So the slope is negative. Sufficient. Hence
C answer