McKinsey Problem Solving Test Free PST Practice by Types




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Reading Facts Practice

Question 1

Reading Facts Practice

 Which of the following statements is valid based on the data provided on the Graph 1 above?

A) If Russia real GDP in 1999 is $1000 billions, its GDP in 2001 is $1045.

B) For most of the time between 1992 and 2000, Ukraine’s real GDP is lower than Russia’s

C) Ukraine’s real GDP in 1998 is equal to it of 1999

D) Ukraine’s real GDP increased between 1994 and 2001

Question 2

Reading Facts Practice

Which of the following statements is valid based on the data provided on Graph 3 above?

A) The Service-to-Agriculture ratio increased by more than 3 times between 1995 and 2007

B) Service GDP in 1995 is more than Industry GDP in 2007

C) Agriculture is where GDP value dropped the most between 1995 and 2007

D) In 2007, Service GDP is no less than 6 times Agriculture GDP

D) In 2007, Service GDP is no less than 6 times Agriculture GDP

Question 3

Reading Facts Practice

On the Average Weekly Spend Per Household columns, you are provided both actual (Area) and target (Base) numbers.

If Spend per Household meet the base target, how many more pounds will be spend in the area?

Word Problem Practice

Question 1

Comfort Taxi is one of the biggest taxi companies in Singapore. Following are some information on this pricing structure:

  • The first 1 km or less: $ 3.50
  • Every 400 m thereafter or less up to the 11th km (10 km after the first km): $ 0.25
  • Every 500 m thereafter or less after 11 km: $ 0.25
  • Peak Period Surcharge: 25% of all cost between 6pm-midnight
  • If a taxi ride is continuous through non-peak and peak hours, Peak Period Surcharge only apply partially to cost incurred within the Peak time frame

Suppose Singapore road speed on peak hours is 30 km/h and 50 km/h for non-peak hours. A rider has $ 23.5 left to travel a distance of 30 km after work.

Which of the following is the minimum minutes the rider has to leave before 6 pm to be certain that he can cover the distance within the left budget?

B) 15 minutes

Question 2

TexasThink is the only retailer of the Lenovo X1 Carbon in Texas. TexasThink is considering a comprehensive marketing plan with the following information:

  • Marketing program costs a monthly amount of $200,000, but will result in 20% increase (NOT 20 percent points) in the conversion rate of each visits to the website
  • Conversion rate of each visits to the website before the program was 5%
  • Margin per laptop sold is $100

Suppose the only sales channel of TexasThink is through its website, all costs stay the same regardless of the program.

What is the minimum number of TexasThink website visits before the comprehensive marketing plan is financially beneficial after the first month?

Root-cause Reason Practice

Question 1

Fletcher is a major Steel producer in the Pacific continent. It has markets in New Zealand, Australia and other South East Asia countries. Of many types of steels, re-bar (reinforced bar) is typically used in high-rises and big construction projects.

There are three main groups of steel consumers in New Zealand:

  • Home owners purchase steel at retail sizes for purposes of self-constructing and self-renovating their homes
  • Scaled private construction companies, who often contracts large construction projects and steel orders
  • State-own Enterprises (SOE), who build government’s projects such as roads, bridges, schools, hospitals, etc. (SOEs usually have bargaining power since steel providers need governments’ permissions in order be legally used in particular countries.)
Root-cause Reason Practice​

C) South East Asia economy will shift toward privatization, so will the construction market

Did you pick A? – Wrong subject
A is not correct because the data in Table is for Re-bar steel, which is not used by home owners.

Did you pick B? – Wrong trend
B is not correct because a heavy weight on SEO will be unfavorable to Re-bar Steel market size (measure by $US) because of the cheaper price from SOEs’ strong bargaining power.

Did you pick D? – Wrong subject
Market size doesn’t have anything to do with production technology and facility. Sales does.

Did you pick C? – Correct subject and correct trend!

Formulae Practice

Question 1

VICEM is a leading cement company in South East Asia. The following data regarding its business and production has been gathered.

Formulae Practice​
Clinker factor is defined as the amount of clinker needed to produce 100 units of cement. Which of the following formulae calculates the amount of clinker (in tons) needed to purchase in a year?

D) [ (p x f) / 100 ] – c

Question 2

Mong Cai and Ha Long are the two main districts of Quang Ninh island. Below are some demographic data about the two districts.

Formulae Practice​
Average number of people per vehicle travel between the two districts is 2.
Assume the traffic in and out the island is minor and people go to work in the morning. Which of the following equations best approximates the amount of vehicle (v) travel from Mong Cai to Ha Long every morning?

Client Interpretation Practice

Question 1

Gangnam Market is a convenience-stores chain mainly in the Gangnam district, Seoul, Korea. Though has been losing money almost every year since 2000, Gangnam Market secures a good deal of strategic locations in the highly populated Gangnam district. Recently, Gangnam Market was acquired by Lotte Mart in its aspiration to expand to the mini-market market. Lotte right away sets up a transformation project to get Gangnam Market back on track. The CEO of Gangnam Market states that aggressive transformation targets are fine for newly acquired stores with similar operation model with Lotte’s big stores, but he hopes that the parent company is realistic about the convenience-stores model Gangnam has been operating with.

Which of the following statements best reflect the concerns of Gangnam Market’s CEO?

C) He is concerned that Lotte Mart’s transformation milestones are not realistic for companies with different operational model from Lotte Mart like Gangnam Market

Here are words or phrase that make the choice wrong. Those are underlined!

A) He is concerned that Gangnam Market will never be able to transform itself into Lotte system becauseGangnam Market only presents in a specific geographic location.

B) He is concerned that Gangnam Market sets transformation milestones that are too aggressive and not realistic for newly acquired companies like Gangnam Market.

C) He is concerned that Lotte Mart’s transformation milestones are not realistic for companies with different operational model from Lotte Mart like Gangnam Market.

D) He is concerned that Lotte Mart’s transformation targets are too high for Gangnam Market because it has been losing money for a while.

Notice all the underlines above, they are all correct based on the case description. However, they are NOT mentioned on the specific assertion of the CEO. Therefore choices that contain them need to be eliminated.

Fact-based Conclusion Practice

Question 1

The McKinsey team has an interview with the Chief Operation of they New Bingham Mine, Salt Lake City. During the interview, the following facts have been gathered:

  • The factory must have at least one safety inspector 24 hours a day, seven days a week, to satisfy Federal and State labor regulations.
  • To maximize operation efficiency, there must be exactly 10 line workers operate the mine
  • The mine operates from 8am until 5pm Monday to Sunday
  • The mine employs 4 safety inspectors and 16 line workers to make 20 direct workers in total
  • Total weekly employee cost for the Bingham mine is $16,000

Which of the following statements is a valid conclusion?

B) At least one safety inspector must work more than 40 hours per week

A – Fit-well but non Fact-based
There are 4 inspectors out of 20 direct workers so it seems like cost of inspector can very well be 1 / 5 of total direct worker cost. But a missing piece of data to conclude that is: each person get similar total income.

C – Fit-well but non Fact-based
The mine open 9 hours per day, 7 days per week, and there must be 10 line workers at a time, so it is 630 man hours per week at the line positions. There are 16 line workers, so on average each must work only 39 hours per week. This seems to fit very well with the proposed conclusion: line workers do not work more than 40 hours per week. However, a missing piece of data to conclude that is: every line workers work a same amount of time (if not, there can be some who work over 40 hours, some others work less).

D – Fit-well but non Fact-based
Similar to A, there are more line workers, so it seems like total cost for line workers is more than total cost for safety inspectors. But a missing piece of data needed to conclude that is: cost of each workers is similar.

Only B is a proven TRUE conclusion based on the provided facts. There are 24 x 7 = 168 inspector hours needed in a week, equally 42 hours per week per inspector. So there must be one who work more than 40 hours.

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Arzu Huseynzade
Arzu Huseynzade

Could you please provide the explanations to the answers, like an answer key?

Housam Bassal
Housam Bassal

For Question 1 of Reading Facts Practice, I think best answer will be B or D? I don’t think is C, could you please help in clarification?!


You are given % changes, not the levels of the variable, so you cannot pass judgement on which is larger (Ukraine or Russia) so you cannot justify B. If you think B is correct is because you are assuming additional knowledge outside the scope of what was given (i.e. Russia Real GDP being larger than Ukraine’s, but this is not given, so you cannot assume it). D is plain wrong as starting 1994 to 1999 all changes are negative, so your base in 1999 is X*(1-0.12)*(1-0.1)*(1-0.03)*(1-0.02)*1 then multiply that times 1.06*1.09 to get to 2001 – Now ignore the value… Read more »

Housam Bassal
Housam Bassal

For Question 2 of Reading Facts Practice, I think the best answer will be D or A? I don’t think is JUST D, could you please help in clarification?!


Again, you are given the SHARE of a variable at two very separate points in time. The variable MUST have evolved, so without knowing HOW it evolved you can discard all options that compare the LEVEL of the variable between 1995 and 2007, so in 10 seconds you already need to know that regardless of what is written the only correct option must be the one that only refers to ONE year (as long as what is written is comparing the LEVELS of the variable).

Housam Bassal
Housam Bassal

Word Problem Practice,Q2 :
100($/converted visit). x(visits) . 5/100 (conversion rate) . 1.2 (20% increase in convertion) > 200,000$
x > 33,333 visits


All you need to care about is what is incremental. The existing 5% conversion is irrelevant, you already have it before investing, so you cannot use it to justify recovering the investment. The incremental 1% conversion needs to pay for the marketing costs. No math needed with $100 margin and incremental conversion of 1%…. 😉