Algebra
posted by Ashley Kate .
Andy has 145 coins in his coin bank. THe number of 5denomination coins is 10 more than twice the number of 10denomination coins. The difference between the number of 1denomination coins and 5denomination coins is 5 more than the number of 10denomination coins. How many of each kind of coin does he have?

tens = t
fives = f
ones = p
then
t+f+p = 145
f = 10+2t
p  f = 5 + t so p = 5+f +t
= 5 + 10+2t + t = 15+3t
so
t + 10+2t + 15+3t = 145
6 t + 25 = 145
6 t = 120
t = 20
p = 15+3(20) = 75
f = 10+2(20) = 50