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I'll take a stab at this (I could be wrong).

--

When Sales are $100:

Sales = $100 ; Gross Profit = $50

This means COGS = $50 and Gross Margins = 50%

Total SG&A = $40 and 25% is variable. This means Variable SG&A is $10 and Fixed SG&A is $30.

EBITDA here is $10 which is = Gross Profit - Total SG&A.

--

Note that when Sales increase, COGS generally increase too as COGS reflects the materials needed to make the products that are being sold and you need more COGS to sell more products. So we can assume that growth in COGS is proportional to growth in Sales at the same Gross Margins.

Regarding SG&A, the Fixed SG&A would remain constant irrespective of Sales while the Variable SG&A would change proportionally with Sales.

--

When Sales increase by 10%:

Sales = $110

Gross Margins = 50% therefore COGS = $55 (as you can see COGS also proportionally increases by 10% just like Sales)

Thus Gross Profit = $55

Total SG&A = Fixed SG&A + Variable SG&A 

Fixed SG&A will stay the same at $30 while Variable SG&A will increase by 10% like Sales. So Variable SG&A = $11.

Thus Total SG&A = $41

EBITDA = Gross Profit - Total SG&A = $55 - $41 = $14

New EBITDA is $14 and EBITDA increases by 40%

--

When Sales decrease by 10%:

Sales = $90

Gross Margins = 50% therefore COGS = $45

Thus Gross Profit = $45

Total SG&A = Fixed SG&A + Variable SG&A = $30 + $9

Thus Total SG&A = $39

EBITDA = Gross Profit - Total SG&A = $45 - $39 = $6

New EBITDA is $6 and EBITDA decreases by 40%

--

 

Ah, a classic PE interview question! Let's break it down:

If sales increase by 10%, they become $110. Since SG&A is 25% variable, it will also increase by 10%, becoming $44. The Gross Profit will increase to $55 (since Gross Profit is Sales minus Cost of Goods Sold, and we're assuming COGS is a variable cost). So, the new EBITDA will be $55 - $44 = $11.

On the other hand, if sales decrease by 10%, they become $90. The variable portion of SG&A will also decrease by 10%, becoming $36. The Gross Profit will decrease to $45. So, the new EBITDA will be $45 - $36 = $9.

Remember, this is a simplified scenario and actual results could vary based on other factors not considered here. But this should give you a good starting point for understanding the relationship between sales, variable costs, and EBITDA. Keep those numbers cranking!

Sources: https://www.wallstreetoasis.com/forum/investment-banking/ebitda-net-working-capital-interview-question?customgpt=1, Got this task during an Private Equity internship interview, how to handle it?, Framework for Understanding Results, Thought Exercise / Interview Question about EBITDA

I'm an AI bot trained on the most helpful WSO content across 17+ years.
 

Can do as above but I think the purpose of this question was to test your knowledge of operating leverage, not mental math abilities.

So a better answer would be one using operating leverage. So clarify that cogs are 100% VC meaning that total VC are 60. OL = Contribution to Marin/ OP margin. So OL = ((100-60)/100/(10/100) = 40%/10% = 4x. And since OL is also = % change in EBITDA/%Change in rev, a 10% increase in rev will cause a 40% inc in EBITDA. And -10% rev =-40% EBITDA.

 
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