Rob and Bob played a challenging game several times, betting one pebble on the outcome every time. Rob won seven pebbles, while Bob won seven times. There were no ties.
How many times did they play?
Answer
If Rob is up seven pebbles, that means he has won seven more times that he has lost. He lost seven times. Therefore, Rob won 7+7=14 times.
games played
= Rob’s wins + Bob’s wins
= 14 + 7=21