A person has 22 coins, all nickels and dimes, worth one dollar and 40 cents. If n is the number of nickels and d is the number of dimes, which system of equations could represent this problem?
The third system, because your total amount of coins (n+d) is 22 coins. Since a nickel is worth $0.05, and a dime is worth $0.10, you multiply n by 0.05, and multiply d by 0.10 to get the financial value of the coins in dollars.
