Bill of Materials

$$ Parent Component

$$ X Y $(3)$

Z $(2)$

$$ Y M $(4)$

N $(1)$

$$ Z O $(2)$

$$ M P $(3)$

Q $(2)$

Given the following parents and components, construct a product tree. Figures in brackets show the quantities per item.

$$ What number of P$\text{'}$s are needed for one unit of X$?$

$$ Which components are purchased directly?