x = # of CDs Walter has
3x - number of CDs Brian has
144 - total
x + 3x = 144
4x = 144
x = 144/4
x = 36
Answer: D. 36
Answer:
D.36
Step-by-step explanation:
X+3X=144
4X=144 (THEN DIVIDE BOTH SIDES B 4)
X=144/4=36
