Amount Lauren had at first = x
(length of the upper bar model)
After buying a dress, the remainder
= r (length of the lower bar model)
From the lower bar model,
$72=3/Sofr=3/5x r
So 1/5 of r =$72/3 = $24, and
r = 5 x $24 = $120
From the upper bar model,
Amount spent on a dress = 0.20x
= 1/5 ofx
So R = 4/5 of X= 4/5 x x, which
implies that
$120 = 4/5 of x = 4/5 x x
So 1/5 ofx = $120/4 = $30, and
x= 5 x $30 $150