Final answer:
The complement of having a 10% chance to go back 2 spaces is drawing any other card, which has a combined probability of 90% as the sum of all probabilities in an event space must equal 100%.
Step-by-step explanation:
The complement of the event where there is a 10% probability of drawing a card that makes you go back 2 spaces in a board game is the probability of drawing any other card that does not have this effect. The probability of this complementary event is 90% because the sum of probabilities for all possible outcomes must equal 1 (or 100%).
Thus, we can deduce that the complement includes all other events such as: going forward any number of spaces, staying in the same place, moving to the end of the board, and any other actions that might be dictated by the game's cards, as long as the action is not going back 2 spaces.