At the local pet store, zebra fish cost $2.10 each and neon tetras cost $1.85 each. If Mary bought 16 fish for a total cost of $31.60, not including tax, how many of each
type of fish did she buy?
a) 8 zebra fish; 8 neon tetras
b)8 zebra fish; 9 neon tetras
c) 14 zebra fish; 2 neon tetras
d) 7 zebra fish: 9 neon tetras