1.Jeff the fly starts at the point (0,0) in the coordinate plane. At each step, Jeff takes a step to the right, left, up, or down. After 10 steps, how many different points could Jeff end up at?

2.Ten points are chosen on a circle. A line segment is drawn between every pair of chosen points. How many line segments are drawn?

Guest Feb 15, 2020

#1**0 **

1. Jeff the fly can reach 10^2 + 9^2 = 181 points.

2. There are 10 ways to choose the first point, then 9 ways to choose the second points, so there are 10*9 = 90 line segments.

Guest Feb 15, 2020

#3**0 **

Ah, that's 90 POINTS on a circle, a line segment is two points touching each other, which means it's 90/2 = 45

AnimalMaster
Feb 15, 2020

#2**0 **

1. the answer that i agree with is here:

https://web2.0calc.com/questions/help-me-please_35236

2. \(\binom{10}{2} = 45\) line segments

atlas9 Feb 15, 2020