Hi All,
Encountered the following DS problem in Kaplan CAT 1. Have put my own reasoning and answer choice below. Point is I got it wrong; the software says the answer is C. Forum members and esp. Kaplan professors, need ur help pls!
At a certain dept store present-wrapping counter, each clerk will wrap no fewer than 20 and no more than 30 presents per hour. If 70 people are standing in line, will all of their presents be wrapped after one hour?
1) Each person in line has at least one present to be wrapped by one of the 6 clerks at the counter.
2) If each person in line had one more present to be wrapped, 9 clerks would be required to guarantee that every present would be wrapped in one hour.
It was obvious why the answer isn't A or D; statement 1 keeps the total no of presents very open ended - there could be 70 or 7000 presents here.
Here's my analysis of statement 2. The moment you require 9 clerks, it means the no of presents exceeds the max capacity of 8 clerks, i.e. 240. So if we consider each of the 70 guests having an extra present, total no of presents would range from 241 till 270 inclusive. Subtract 70, you get 171 till 200 inclusive (actual no of presents). If it's 180 or less, no of clerks needed is 6. If it's 181 till 200, 7 will suffice. Hence statement 2 doesn't suffice alone.
C is also incorrect: statement 1 tells us there are 6 clerks, statement 2 tells us the total no of presents would require 6 clerks or 7.
Hence the only remaining answer is E.
That was my solution. The Kaplan solution says the answer is C (both together suffice). It assumes that in statement 2, when each person in line has an additional present, total no of presents becomes 180 (9x20). From there it goes on to say that both statements together give us no of presents and clerks, so answer choice C is correct.
Once again, Kaplan tutors or GMAT titans out there, can u pls shed some light on this?
Thx, H
Encountered the following DS problem in Kaplan CAT 1. Have put my own reasoning and answer choice below. Point is I got it wrong; the software says the answer is C. Forum members and esp. Kaplan professors, need ur help pls!
At a certain dept store present-wrapping counter, each clerk will wrap no fewer than 20 and no more than 30 presents per hour. If 70 people are standing in line, will all of their presents be wrapped after one hour?
1) Each person in line has at least one present to be wrapped by one of the 6 clerks at the counter.
2) If each person in line had one more present to be wrapped, 9 clerks would be required to guarantee that every present would be wrapped in one hour.
It was obvious why the answer isn't A or D; statement 1 keeps the total no of presents very open ended - there could be 70 or 7000 presents here.
Here's my analysis of statement 2. The moment you require 9 clerks, it means the no of presents exceeds the max capacity of 8 clerks, i.e. 240. So if we consider each of the 70 guests having an extra present, total no of presents would range from 241 till 270 inclusive. Subtract 70, you get 171 till 200 inclusive (actual no of presents). If it's 180 or less, no of clerks needed is 6. If it's 181 till 200, 7 will suffice. Hence statement 2 doesn't suffice alone.
C is also incorrect: statement 1 tells us there are 6 clerks, statement 2 tells us the total no of presents would require 6 clerks or 7.
Hence the only remaining answer is E.
That was my solution. The Kaplan solution says the answer is C (both together suffice). It assumes that in statement 2, when each person in line has an additional present, total no of presents becomes 180 (9x20). From there it goes on to say that both statements together give us no of presents and clerks, so answer choice C is correct.
Once again, Kaplan tutors or GMAT titans out there, can u pls shed some light on this?
Thx, H
