Suppose you have 20 coins that total $3.00. Some coins are nickels and some are quarters. Which of the following pairs of equations would you use to find out how many of each coin you have?

A. n + q = 30

5n + 25q = 20

B. n + q = 30

n + q = 3.00

C. n + q = 3.0020

0.05n + 0.25q = 3.00

D. n + q = 20

5n + 25q = 300

Answer: D. n + q = 20

5n + 25q = 300

Step-by-step explanation:

Let n represent the number of nickels that you have.

Let q represent the number of quarters that you have.

Suppose you have 20 coins. It means that

n + q = 20

The total value of the coins is $3. The value of a quarter is $0.25 and the value if a nickel is $0.05. Therefore, the equation would be

0.05n + 0.25q = 3

Multiplying both sides of the equation by 100, it becomes

5n + 25q = 300

The correct option is

D. n + q = 20

5n + 25q = 300