Gelb Company currently makes a key part for its main product. Making this part incurs per unit variable costs of $$1\mathrm{.}70$

for direct materials and $$1\mathrm{.}25$ for direct labor. Incremental overhead to make this part is $$1\mathrm{.}60$ per unit. The company

can buy the part for $$4\mathrm{.}80$ per unit.

$($a$)$ Prepare a make or buy analysis of costs for this part. $($Enter your answers rounded to $2$ decimal places.$)$

$($b$)$ Should Gelb make or buy the part?