Question 366251
let x = total number of coins.  Then x/5 = # of dimes, 2x/15 = # of nickels, and 2x/3 = # of pennies.  Then 
{{{(x/5)*0.10 + (2x/15)*0.05 + (2x/3)*0.01 = 1.00}}},
{{{0.30x + 0.10x + 0.10x = 15}}}, after multiplying both sides by 15.
{{{0.50x = 15}}},
x = 30.
Thus there are 6 dimes, 4 nickels, and 20 pennies.