The enormous state university good works society recently raised funds for three worthwhile causes: the math professors' benevolent fund (mpbf), the society of computer nerds (scn), and the ny jets. because the society's members are closet jocks, the society donated twice as much to the ny jets as to the mpbf, and equal amounts to the first two funds (it is unable to distinguish between mathematicians and nerds). further, for every $1 it gave to the mpbf, it decided to keep $1 for itself; for every $1 it gave to the scn, it kept $2, and for every $1 to the jets, it also kept $2. the treasurer of the society, johnny treasure, was required to itemize all donations for the dean of students, but discovered to his consternation that he had lost all the receipts! the only information available to him was that the society's bank account had swelled by $4200. how much did the society donate to each cause?