$小王加工的零件个数占总个数的:$
$\ (1-\frac{7}{30}) × \frac{14}{14+9}=\frac{14}{30}\ $
$小李加工的零件个数占总个数的:$
$1-\frac{7}{30}-\frac{14}{30}=\frac{9}{30}$
$总个数:50÷(\frac{14}{30}-\frac{9}{30})=300(个)\ $
$小张:300×\frac{7}{30}=70(个)\ $
$小王:300×\frac{14}{30}=140(个)\ $
$小李:300×\frac{9}{30}=90(个)\ $
$答:小张加工70个,小王140个,小李90个。$