How many coins in the piggy bank

Maria has a piggy bank at home full of nickels and dimes. She has $14.75 in the bank. there are 20 more dimes than nickels. How many of each type of coin are in the piggy bank?

x = number of nickels
x + 20 = number of dimes {there are 20 more dimes than nickels} 

0.05x + 0.1(x + 20) = 14.75   {value of coin multiplied by number of coins equals total value}
0.05x + 0.1x + 2 = 14.75   {used distributive property}
0.15x + 2 = 14.75   {combined like terms}
0.15x = 12.75   {subtracted 2 from each side}
x = 85   {divided each side by 0.15}
x + 20 = 105   {substituted 85, in for x, into x + 20} 

85 nickels and 35 dimes

- Algebra House