Data Sufficiency 2

[arbiter]

Marta bought several pencils. If each pencil was either a 23-cent pencil or 21-cent pencil, how many 23-cent pencils did Marta buy?

1>marta bought a total of 6 pencils
2>the total vaue of the pencils Marta bought was 130 cents.

OA is B

[imhimanshu]

Hi
Pls use spoiler for OA else post it later...coz one may not be able to apply logic.....

[imhimanshu]

so Here you go:
Statement 1-> one cant find out how many pencils did he purchased...coz may be he purchased all 6 pencils of 23 cents or of 21 cents. So Insufficient. options A and D out.
Statement 2->
the total vaue of the pencils Marta bought was 130 cents.
i.e 23(x)+21(y)=130 .....(1)
where x and y number of pencils. Now we need to find x and y , also, there should be one and only one set that needs to be satifying the above equation. Otherwise statement B alone wont be able to answer the question.

By hit and trial:
x=2 and y=4 Hence B
also none other seems to satisfy eqn (1)