Answer: 
<u>Step-by-step explanation:</u>
![\text{Use the distance formula: }d_AB=\sqrt{(x_A-x_B)^2+(y_A-y_B)^2}\\where\ (X_A, y_A)=(-3, -2)\\and\ (x_B,y_B)=(4, -7)\\\\\\d_AB=\sqrt{(-3-4)^2+[-2-(-7)]^2}\\\\.\quad =\sqrt{(-7)^2+(5)^2}\\\\.\quad =\sqrt{49+25}\\\\.\quad =\boxed{\sqrt{74}}](https://tex.z-dn.net/?f=%5Ctext%7BUse%20the%20distance%20formula%3A%20%7Dd_AB%3D%5Csqrt%7B%28x_A-x_B%29%5E2%2B%28y_A-y_B%29%5E2%7D%5C%5Cwhere%5C%20%28X_A%2C%20y_A%29%3D%28-3%2C%20-2%29%5C%5Cand%5C%20%28x_B%2Cy_B%29%3D%284%2C%20-7%29%5C%5C%5C%5C%5C%5Cd_AB%3D%5Csqrt%7B%28-3-4%29%5E2%2B%5B-2-%28-7%29%5D%5E2%7D%5C%5C%5C%5C.%5Cquad%20%3D%5Csqrt%7B%28-7%29%5E2%2B%285%29%5E2%7D%5C%5C%5C%5C.%5Cquad%20%3D%5Csqrt%7B49%2B25%7D%5C%5C%5C%5C.%5Cquad%20%3D%5Cboxed%7B%5Csqrt%7B74%7D%7D)
Well. add all of these up 8+5+5. we know 5+5 is 10. and 10+8 is 18. so 18 is the denominator. There are 8 red markers and 5 blue markers at 8 and 5 up. 8+5 is 13 right? So the numerator will be 13. but the probability of picking a blue then a red is 13 alone or if you are ask for out of the amount of markers there are, its 13/18. so the probability is 13 or 13/18.
