Answer:
a) 275,000 boxed per year
b) sales price of $ 11.04
c) <em> sale volume in dollars 4.830.967,74</em>
Explanation:
selling price: $ 9.60
Variable cost: $<u> 5.76</u>
Contribution: $ 3.84
Contribution Ratio: 3.84 / 9.60 = 40%

1,056,000 / 3.84 = <em>275,000</em>
<em />
<em>If Variable cost increase by 15%</em>
<em>To keep contribution ratio at 40% then selling price should be:</em>
(<em>X - 5.76 x 1.15) / X = 0.40</em>
<em>X = $ 11.04</em>
To keep the same income but without changing price:
current income: (sales x contribution less fixed cost)
(390,000 x 3.84 - 1,056,000) = 441,600
contribution: <em>(9.60 - 5.76 x 1.15) / 9.60 = 0.31</em>

<em>(1,056,000 + 441,600)/ 0.31 = </em>
<em>1.497.600 / 0.31 =</em><em> 4.830.967,74</em>