You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: A bag contains 5 red balls, 5 green balls and 6 white balls. A ball is drawn at
random from the box. What is the probability that the ball drawn is either red or green?

 Option A: 2/5

 Option B: 3/5

 Option C: 1/5

 Option D: 7/15

 Option E: 5/8
Option E

Question: Each of the integers from 0 to 9, inclusive, is written on a separate slip of blank paper and the ten slips are dropped into hat. If the slips are then drawn one at a time without replacement, how many must be drawn to ensure that the numbers on two of the slips drawn will have a sum of 9?

 Option A: 2

 Option B: 3

 Option C: 1

 Option D: 6

 Option E: 4
Option D

Question: A and B walk around a circular track. They start at 9 a.m. from the same point in the opposite directions. A and B walk at a speed of 2 rounds per hour and 3 rounds per hour respectively. How many times shall they cross each other before 10:00 a.m.?

 Option A: 8

 Option B: 7

 Option C: 6

 Option D: 5

 Option E: 10

Option E