millie has a jar of pennies. nickels and dimes. there are 81 coins worth 3.39, there are 3 more nickels than pennies and dimes combines. how many of each coin is there?

Answer 1

p - ?

d - ?

n = p + d + 3

p + d + n = 81

p + 10d + 5n = 339 (3 equations, 3 unknowns)

2p + 2d + 3 = 81 -> 2p + 2d = 78 -> p + d = 39 -> p = 39 - d

n = p + d + 3 = 42

39 - d + 10d + 5*42 = 339

9d = 90

d = 10

p = 39 - d = 39 - 10 = 29