Izzyjust5 wrote:
5 of the 15 lines which have a positive slope have y intercept >> 0, not 5 of the total 35 lines have y intercept >> 0
In general, it is possible to have lines with NO y-intercept. Those lines never intersect the y-axis, or in other words, those lines are vertical (parallel to the y-axis). It is not the same as having a zero y-intercept. If a line is vertical and has a zero y-intercept, it is y-axis.
In this question, the stem clearly states that "A student draws 35 lines in the XY plane, none of which are vertical..." so it's not possible to have lines with NO y-intercept in this case.
Hope it's clear.
I think you did not understand my question correctly.
May be I am missing something
total 35 lines , 15 have positive slope and 20 have 0 or negative slope ( 20 + 15 = 35)
out of 15 having positive slope, 5 have positive Y intercept
So 10 having positive slope have 0 or negative Y intercept
So total 15 lines have positive slope = 5 lines have positive y intercept and 10 lines have , zero or negative y intercept.
also we know total 23 lines have y intercept \(\leq\) 0
so 23 + 5 = 28 , what kind of y intercept do the remaining 7 lines have ?
hope now my question is clear.
Edit:Thank you , understood it , the answer I was looking for was this :
Those 7 lines have positive y intercept but negative slope .
So here is the break up
Total 12 have positive y intercept out of which 5 have positive slope and 7 have negative slope
total 23 have zero or negative Y intercept out of which 10 have positive slope and 13 have 0 or negative slope .
total 35 lines are now accounted for .