two lines L1 and L2 pass through the point of intersection of 2y=x-13 and 3y+x+12=0.L1 passes through P(-4,-7) and L2 is perpendicular to 2x-5y=4. Find the acute angle between L1 and L2.

The probability that a student graduating from suburban state university has student loans to pay off after graduation is .60. if two students are randomly selected from this university, what is the probability that neither of them has student loans to pay off after graduation?