math
posted by lexis green .
A group of friends went to Mudville to watch the Mudville Sluggers play baseball. On the way to the game, three people rode in each car and seven took the train. On the way home, four people rode in each car and two people took the train. The same number of cars and people traveled to and from the game. How many friends could have been in the group? How many cars were used? (please show your work) :)

let the number of cars be x
1st trip:
number of people = 3x + 7
return trip:
number of people = 4x + 2
4x + 2 = 3x + 7
x = 5
So there were 5 cars
the number of people was 3(5) + 7 = 22 
a sack contain 10 blue and 6 red crayons another sack contains 9 blue and 12 red crayons two crayons are drown at random without replacement from each sack. what is the probability that all the four crayons are blue? exactly one of the four crayons is red