$(10$ pts$)$

The table below shows the marginal cost, in dollars per item, based on the number of items produced.

$\backslash$table$[[\backslash$table$[[$Production$],[$level$],[($items$)]],10,20,30,40,50,60],[\backslash$table$[[$Marginal$],[$Cost$],[($dollars$],[$per item$)]],49\mathrm{.}50,49\mathrm{.}10,48\mathrm{.}50,48\mathrm{.}25,47,45\mathrm{.}50]]$

a$.$ Find a lower estimate for the cost to increase production from $10$ items to $60$ items. Is this a left sum or a right sum? Include units!

b$.$ Find an upper estimate for the cost to increase production from $10$ items to $60$ items. Is this a left sum or a right sum? Include units!

c$.$ Find an average sum

Can you show all work step by step and all written work