Data Sufficiency

What was the value of the sales of Anderson Books in 2000?

(1) The sales of Anderson Books grew by $25,000 each year from 1990 to 2000.

(2) The value of the sales of Anderson Books doubled between 1990 and 2000.

Beyond just answering, can someone write out a detailed explanation if its not too much trouble. Thanks

Oh yeah OA C

osirus0830 wrote:What was the value of the sales of Anderson Books in 2000?

(1) The sales of Anderson Books grew by $25,000 each year from 1990 to 2000.

(2) The value of the sales of Anderson Books doubled between 1990 and 2000.

Beyond just answering, can someone write out a detailed explanation if its not too much trouble. Thanks

Oh yeah OA C

St 1 Let X be the sales in 1990. SO in 2000 sales would have been Y= X+ 25000 *10 =X+250000

St 2: Sales in 2000 Y =2*X

Combining : 2*X= X+250000
X=250000
Y: 2*250000= $ 500000

Thanks so much. I think the trouble I had, I originally set it up like a series, and wasn't sure how to incorporate the information from statement two into equations to solve. Thanks.

osirus0830 wrote:What was the value of the sales of Anderson Books in 2000?

(1) The sales of Anderson Books grew by $25,000 each year from 1990 to 2000.

(2) The value of the sales of Anderson Books doubled between 1990 and 2000.

Beyond just answering, can someone write out a detailed explanation if its not too much trouble. Thanks

Oh yeah OA C

St1: it just tells you that the amount grew by 25,000 each year. However, you don't know the starting value.

Hence , insufficient.

St2: it just tells that in '90 it was X and in '00 it was 2X.

Hence, insufficient.

Combo:

Don't do the math.

first statement tells you that the amount increased by 25,000 for 10 years and the second tells you that this increase was equal to the amount in '90, twice of which can give you the amount in '00.

that's it! you've got your answer. option C!

osirus0830 wrote:Thanks so much. I think the trouble I had, I originally set it up like a series, and wasn't sure how to incorporate the information from statement two into equations to solve. Thanks.

Here's the great thing about DS: even if you don't know how to set up the two equations, as long as you recognize that you have two distinct linear equations and two unknowns, you have sufficiency.

The concept of "# of equations vs # of unknowns" is THE most powerful tool in DS.

Stuart Kovinsky wrote:

osirus0830 wrote:Thanks so much. I think the trouble I had, I originally set it up like a series, and wasn't sure how to incorporate the information from statement two into equations to solve. Thanks.

Here's the great thing about DS: even if you don't know how to set up the two equations, as long as you recognize that you have two distinct linear equations and two unknowns, you have sufficiency.

The concept of "# of equations vs # of unknowns" is THE most powerful tool in DS.

Thanks, you're right and I will definitely keep that in mind going forward.

Good One ! Thanks to all !