#### Answer

$25\%$

#### Work Step by Step

RECALL:
$R=\dfrac{P}{B}$ where $B$=base, $P$=part, and $R$= rate or percent
The given problem has:
$B=0.600$ grain
$P=0.150\%$
Solve for $R$ using the formula above to obtain:
$R = \dfrac{P}{B}
\\R = \dfrac{0.150}{0.600}
\\P=0.25
\\P=0.25 \times 100\%
\\P=25\$$
Thus, $0.150$ grain is $25\%$ of $0.600$ grain.