Robin, Ashley, Joy, and Christina collected a total of 156 acorns to make fall decorations. Robin collected three times as many acorns as Ashley. Christina has 12 more acorns than Robin. Ashley and Joy collected the same number of acorns.
How many acorns did Ashley collect?
Let x be the number of acorns Ashley collected.
Robin collected 3*x acorns.
Christina collected 3*x+12 acorns.
Ashley + Joy's acorns + Robin's acorns + Christina's acorns = x + x + 3*x + 3*x+12 = 7*x+12 = 156 acorns
7*x = 144 acorns
x = <<20=20>>20 acorns
Ashley collected 20 acorns. Answer: \boxed{20}.