clipea12 :

Statement 1 : It doesn't say any information about how many small dressers did jose bought. Apart from saying,

Number of small= number of large. So insufficient.

Statement 2: It says total amount is 280 dollars.

let, L=large & S=small.

31L + 25S= 280.

It may look insufficient in the beginning. But if you look closely, and plugging values you can find.

If S=10 and L=1. We get 281. So the total number of large and small dressers should be less 11.

So if you continue doing that, we get only one value gives us 280, that is 5.

31*5 + 25*5= 155+ 125=280.

Other method is that when you add the unit digit of multiple of 31 and multiple of 25 should give us 0 and it should be 280 as well.

When you multiply 25 with any number the unit digit will either be 0 or 5. Never other numbers so we can eliminate- 1 to 9(apart from 5).

And if unit digit is 0. then unit digit for multiple of 31 also be 0. But we get only in 310. So unit digit of 25 cannot be 0.

you can go about like this and find that only when we multiple 5 to both 31 and 25. We get a sum of 280.

Statement 2 is sufficient.

How to check, whether 5 will be only number?. Well, we can now look at statement-1(NOTE: Just to verify, not while solving). In GMAT, the both statements never contradicts each other.

St.1 says Number of large dresser=Number of small dresser. So 5 is the number of small dresser.

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