A box contains 7 red, 14 yellow, 21 green, 42 blues and 84 purple marbles. Find the odds in favor of the selection when a marble is chosen at random:

yellow

2 to 11

4 to 11

3 to 11

1 to 11

From the given, there are 14 yellow marbles. 154 are of different colors other and are not yellow. When we speak of "odds in favor", we divide the number of ways a certain event can occur by the number of ways it cannot occur. Mathematically, this can be,

odds = 14 / 154

Simplifying,

odds = 2/11

The answer to this item is first choice.