For a school Halloween party, Brad and Eric had a total of 20 yards of material to make costumes. Brad uses three times more material to make his costume than Eric used and 2 yards of material were left over. How many yards did Brad and Eric use?
amount used by Eric --- x
amount used by Brad --- 3x
x + 3x + 2 = 30
4x=28
x=7
Eric used 7 yds and Brad used 21
check:
30 - 7 - 21 = 2 ✔