A bag contains purple marbles and green marbles, 39 in total. The number of purple marbles is 9 less than 5 times the number of green marbles. How many purple marbles are there?

Let x = the # of purle marbles

Let y = the # of green marbles

x + y = 39

x = 5y - 9

Substitute the value of x into the first equation

5y - 9 + y = 39

Add like terms

6y - 9 = 39

Add 9 to both sides

6y = 48

Divide both sides by 6

y = 8

Substitute the value of y into the second equation of x = 5y - 9

x = 5 (8) - 9

x = 40 - 9

x = 31

Therefore the answer is 31 puple marbles and 8 green marbles.