George has $3.71 in pennies, nickels dimes and quarters in his pocket. he has twice as many dimes as nickels, two more nickels than quarters, and three fewer pennies than three times the number of nickels. how many of each kind of coin does he have

pennies = 0.01 $
 nickels = 0.05 $
 dimes = 0.1 $
 quarters = 0.25 $
 We must write the system of equations that best suits this problem and solve it:
 Let:
 x = pennies
 y = nickels
 z = dimes
 w = quarters
 Writing the equations
 0.01x + 0.05y + 0.1z + 0.25w = 3.71
 I have twice as many dimes as nickels
 z = 2y
 two more nickels than quarters
 y = w + 2
 three fewer pennies than three times the number of nickels
 x = 3y-3.
 Solving the system of equations:
 x = 21
 y = 8
 z = 16
 w = 6
 answer
 He has
 21 pennies
 8 nickels
 16 dimes
 6 quarters