Answer:
Amy has 12 5¢ coins
Step-by-step explanation:
Let <em>x</em> represent 20¢ coins and <em>y</em> represent 5¢ coins.
Amy has four more 20¢ coins than 5¢ coins. Hence:
And the total value of all her coins is $3.80. Thus:
This yields a system of equations:
We can solve by substitution. Substitute the first equation into the first:
Distribute:
Combine like terms:
And divide both sides by 0.25. Hence:
Thus, Amy has 12 5¢ coins.
Using the first equation:
Substitute:
Thus, Amy has 16 20¢ coins.
In conclusion, Amy has 12 5¢ coins and 16 20¢ coins.