Very interesting equations DS

[ap1010]

Jim bought some pencils for $0.35 each and some notebooks for $0.45 each. How many notebooks did he buy ?

(1) He bought same number of Notebooks and Pencils
(2) He spent a total of $3.2 on the notebooks and Pencils

SPOILER: B

[Shooter]

For our convenience let us multiply all the numbers by 100.

Given eqn: 35P+45N ;N=?

(I) P=N ; 35P+45P nothing helps as we dont have RHS of the eqn.

(II) 35P+45N=320
=> 7P+9N=64

Only when P=4 and N=4 the eqn holds good. We can have different decimals but number of pencils and number of notebook cant be in decimals. SUFF

[ap1010]

Hmm....great...I was trying to do it using decimals ...and was just wondering how to know that there is only possible solution for (2). I like your approach Shooter - to make the equation simple....and in that way its quite evident that 4 is the answer