I had interviews with Booz & Company (Booz Allen Hamilton) and I got accepted for a Consultant Position (once I finished My MBA with distinction from LAU and some 2- 3 years of Experience) : McKinsey , Boston Scientific and Top Tier Global Consultancy Companies share a very similar way of interviews.
At Booz I have 4 Interviews (All Technical) 2 In the Morning and 2 In The Evening (When I passed the 1st round of the 1st two interviews they called to conduct the 2nd round that consisted of two interviews also.
All were consultancy base scenarios (The interviewer a senior consultant usually acts as the "client" that he is facing a problem and you as a consultant you need to solve it. You need to see what is the problem , to investigate more by asking question and getting inputs (usually numerical : You have a paper and pen with no Calculator to analysis , apply financial formulas to give an output / estimations). Each interviewer has a mark sheet to evaluate you (you analysis , your confidence , your formality (suit and shaved) , your chair posture , and output). No direct right answer , rather the analysis part you will be evaluated on your acquired competences , how to deal with numbers , the formulas you know , and how to deal with pressure (each interview time is 30 min only). It can be investment break even analysis ((NPVs , IRR , Capital Cost etc..) , market drilling to know the market share , business transformation , or FP&A - these cases are given usually to General / Strategy Consultancy. The IT/infrastructure consultancy is more narrow and IT Oriented like ERDs , UMLs, Business Analysis , Functional Requirements.
My Experience:
Interview 1: (Potential Market Share Analysis): Gillette has entered the Lebanese Market with a new razor blade for the men , what is the potential market share - Very Ambiguous You assume (remember no right direct answer) rather logical and how you deal with pressure and numbers: Up- to Down Approach Drilling: Population is 4 Million , 40% Males , 0.4 * 4 million = x , from these x about 60 % shave , 0.6 *x = y , (You may assume or ask - Gillette is a well know brand it acquires 80 of the Lebanese Market = 0.8*y , Age Bracket ogf this razor can be introduced too etc..
Interview 2: Break Even Analysis / Investment Analysis: You entered with you friend to a restuarant and you friend can attracted to this restaurant , and he decided to make an investment by purchasing it , discuss his investment making decision. To have a good investment it must break even, thus NPV = 0 , NPV = CF (year 1) / (cost of capital) + CF(year 2) (Cost of Capital)^2 for a restaurant
Cash Flow = Cash In - Cash Out , Cash In = Revenues and Cash Out = Variable Expenses + Fixed Expenses , Variable Expenses Example (COGS ) Fixed (Rent) etc...
Interview 3 : Making a Power Point Presentation and discuss the financial condition of a company , You apply few Ratios (Given P/L and Balance Sheet Statements) Ratios: Cash Conversion Cycle , Interest Coverage Ratio , Debt Ratio , Profitability Ratio , Gross Profit Margin , etc...
Interview 4: If a company wants to pay less taxes it uses FIFO or Lifo (that is a tricky one but straight forward): Cost of Good Sold = Beginning Inventory + Net Purchases - Ending Inventory.
FiFO: First In First Out thus it decrease the ending inventory , resulting in a higher COGS resulting in a lower Income = paying lEss as a taxes
LIFO: Last In Last Out it increases ending inventory = COGS will decrease , Net Income will Increases , more taxes will be paid.
Method:
I frankly Reviewed MBA concepts (mainly Financial Accounting , Financial Management and Some Marketing Analysis). You need to search at Amazon or Online Sources , In Lebanon most probably you need visit LAU/AUB Libraries or if you know some one has access to get an abstract copy of consultancy case analysis. Probe and search.
https://www.google.com.lb/?gws_rd=cr,ssl&ei=44u_Ve_7DITm7gb0x5uICQ#q=preparing+for+case+interviews
By the way mate what Degrees you have mate , your experience , you graduated from where , and how you applied and get invited for interview. Mckinsey screening selection is very tough (Dubai Office Right) - more tougher than Booz Allen Hamilton. But interviews they come in par.
Good Luck !