How many photocopies can you make for $2.00 at the rate of three copies for ten cents?

Im not 100% that thats correct but im pretty sure it is.

Convert $2 to cents, which is 200 cents.
10 cents =3 copies
200/10 =20
20x3 =60copies

or
10 cents =3copies,
100 cents =30copies.
100 x 2 =200cents.
2x30 copies =60 copies.

or in ratio form
10cents : 3copies
multiply 20 to get 200, you need to multiply on both sides,
= 200cents : 60copies

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

No he does not because he can only cover 12 square feet from 15 square feet which he will still need 3 more. this is because if 3×5=15 square feet and 15-12=3 which thats the answer