Data Sufficiency

AAPL wrote:GMAT Paper Tests

Last Friday a certain shop sold 3/4 of the sweaters in its inventory. Each sweater sold for $20. What was the total revenue last Friday from the sale of this sweaters?

1) When the shop opened last Friday, there were 160 sweaters in its inventory.
2) All but 40 sweaters in the shop's inventory were sold last Friday.

Given: Last Friday a certain shop sold 3/4 of the sweaters in its inventory. Each sweater sold for $20.

Target question: What was the total revenue last Friday from the sale of this sweaters?

Statement 1: When the shop opened last Friday, there were 160 sweaters in its inventory.
3/4 of 160 = 120
So, 120 sweaters were sold at a cost of $20 per sweater.
120 x $20 = $2400. So, the total revenue from sweaters was $2400
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: All but 40 sweaters in the shop's inventory were sold last Friday.
If 3/4 of sweaters were sold, then 1/4 of the sweaters were NOT sold
In other words, 40 represents 1/4 of the sweater inventory on Friday morning.
1/4 of 160 = 40
So, when the shop opened last Friday, there were 160 sweaters in the inventory
IMPORTANT: we've now arrived at a point that's the same as statement 1.
So, if statement 1 is sufficient, it must be the case that statement 2 is sufficient.

Answer: D

Cheers,
Brent

AAPL wrote:GMAT Paper Tests

Last Friday a certain shop sold 3/4 of the sweaters in its inventory. Each sweater sold for $20. What was the total revenue last Friday from the sale of this sweaters?

1) When the shop opened last Friday, there were 160 sweaters in its inventory.
2) All but 40 sweaters in the shop's inventory were sold last Friday.

OA D.

Say the inventory of sweaters in the shop on last Friday was x, thus 3x/4 numbers of sweaters were sold.

Total revenue last Friday from the sale of this sweaters = 3x/4 * 20 = 15x.

If we get the value of x, we get the answer.

Question rephrased: What's the value of x, the inventory of sweaters in the shop last Friday?

Let's take each statement one by one.

1) When the shop opened last Friday, there were 160 sweaters in its inventory.

=> x = 160. Sufficient.

2) All but 40 sweaters in the shop's inventory were sold last Friday.

=> x - 40 = 3x/4

=> x = 160. Sufficient.

The correct answer: D

Hope this helps!

-Jay
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