How many more firsttime jobless claims were filed in week P than in week T?
1) for weeks P, Q, R, and S, the avg number of firsttime jobless claims filed was 388,250
2) for weeks Q, R, S, and T, the avg number of firsttime jobless claims filed was 383,000
Answ: C
Please explain. Thanks!!!
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 tendays2go
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Yes, C is the soln.
(i) =>
P+Q+R+S = (388,250 * 4)
(ii) =>
Q+R+S+T= (383,000 * 4)
Now, we have to find PT which is equal to:
[P+Q+R+S]  [Q+R+S+T]
= (388,250  383,000) *4
Hence both the choices combined yield the required value
(i) =>
P+Q+R+S = (388,250 * 4)
(ii) =>
Q+R+S+T= (383,000 * 4)
Now, we have to find PT which is equal to:
[P+Q+R+S]  [Q+R+S+T]
= (388,250  383,000) *4
Hence both the choices combined yield the required value

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we need to find the value of PT
St 1 tells us P+Q+R+S = 388250*4
P = 388250*4QRS
But since it doesnt tell us anything about T its INSUFF
St 2 tells us Q+R+S+T = 383000*4
T=383000*4QRS
but since it doesnt tell us anything about P its INSUFF
Combining them we get
P = 388250*4QRS
T=383000*4QRS
Subtract the two statements we get PT = (388250*4)(383000*4)
Hence the answer is C
St 1 tells us P+Q+R+S = 388250*4
P = 388250*4QRS
But since it doesnt tell us anything about T its INSUFF
St 2 tells us Q+R+S+T = 383000*4
T=383000*4QRS
but since it doesnt tell us anything about P its INSUFF
Combining them we get
P = 388250*4QRS
T=383000*4QRS
Subtract the two statements we get PT = (388250*4)(383000*4)
Hence the answer is C
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First thing to note is this is DS, so we don't need to actually calcuate. As soon as you see you have enough info, you're done.vladmire wrote:If we are trying to find the difference in the number of jobless claims between the 2 weeks why do we multiply 4? I thought P+Q+R+S/4 gave us $388,250 so whats the point in multiplying 4
(388,250  383,000) *4 to yield the required value?
On this particular question, as long as you know the average formula, you should reach (C) very quickly by combining the two equations you get.
If we actually wanted to solve, we need to multiply by 4 precisely because of the equation you provided.
(P+Q+R+S)/4 = 388250
(Q+R+S+T)/4 = 383000
Rearranging to make it easier to get the relationship (PT) that we want:
P+Q+R+S = 4(388250)
T+Q+R+S = 4(383000)
Subtracting the second equation from the first:
PT = 4(388250)  4(383000)
PT = 4(388250  383000)
PT = 4(5250)
PT = 21000
We could have just multiplied both big numbers by 4 before doing the subtraction, but it's much easier to do the arithmetic with smaller numbers.
Stuart Kovinsky  Kaplan GMAT Faculty  Toronto
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