You roll a 6-sided die with faces numbered 1 through 6, and toss a coin. what is the probability of rolling a 2 or getting heads? a.1/6
b. 5/12
c. 2/3
d. 1/12

In this instance a die is rolled and a coin is tossed. both events are independent of each other. the results of one event will not affect the results of the other event 
event 1 - rolling a die
there are 6 sides with 1 side having 2
probability of getting 2 - 1/6
event 2 - tossing a coin 
2 sides of which one is heads
probability of getting heads - 1/2

when we find the probability of rolling a 2 OR getting heads then we one of these events can happen or both the events can happen. 
then we need to add the 2 probabilities of these 2 events happening 

therefore probability of rolling a 2 or getting heads  =  1/6 + 1/2
bring the fractions to a common denominator 6
1/2 multiply whole fraction by 3 --> 3/6
add the fractions 

4/6 can be simplified by dividing whole fraction by 2 

answer is 2/3

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.