Question

A person has 20 coins, all nickels and dimes, worth one dollar and 40 cents. How many nickels are there?

If n = number of nickels and d = number of dimes, which system of equations represents the problem?



n + d = 20 and n + d = 1.40

n + d = 20 and 5n + 10d = 1.40

n + d = 20 and 5n + 10d = 140

Answer 1

The number of nickels added to the number of dimes equal 20. And that about multiplied by the values of the coins will equal the amount of money all together.

Answer 2

amount*

Answer 3

Does this help?