Sasha has some pennies, nickels, and dimes in her pocket. The number of coins is 18. The expression $\displaystyle{0.01}{p}+{0.05}{n}+{0.10}{d}\usepackage{cmbright}\Huge\$ represents the value of the coins, which is $1.08. She has twice as many dimes as pennies. How many of each coin does Sasha have?