Michelle has a jar of quarters and dimes totalling to 3.10 if there are sixteen coins in the jar how many more quarters are there than dimes?

Q + d = 16 ... q = 16 - d

0.25q + 0.10d = 3.10

0.25 (16 - d) + 0.10d = 3.10

4 - 0.25d + 0.10d = 3.10

-0.25d + 0.10d = 3.10 - 4

-0.15d = - 0.90

d = - 0.90/-0.15

d = 6 ... dimes

q + d = 16

q + 6 = 16

q = 16 - 6

q = 10 ... quarters

so there are (10 - 6) = 4 more quarters then dimes