A collection of nickels and quarters is worth $2.10. There are 22 coins in all . How many of each coin are there?

17 nickels

5 quarters

Step-by-step explanation:

Let n = no. of nickels

22 - n = no. of quarters

Each quarter is 25 cents and each nickel is 5 cents

5n = total amount of money in cents for the nickels

25(22 - n) = total amount of money in cents for the quarters

Since the total amount of money is $2.10 or 210 cents we have the equation

5n + 25(22 - n) = 210

5n + 550 - 25n = 210

-20n + 550 = 210

-20n = -340

n = 17 nickels

22 - n = 22 - 17 = 5 quarters

Now, you don't need to do all that I did.  I explained in detail what is going on in this problem.  All that you would need to do is write this:

let n = no. of nickels

22 - n = no. of quarters      and then write the equation and solve

5n + 25(22 - n) = 210

??                                          OK?

first option

a function is a relation in which an input is paired with exactly one output.

so, let's find the right answer.

in our first option, our inputs are january, february, and march. the outputs are 30, 28, and 25. each input has it's own output. this is correct!

our second option we know is incorrect, because ms. valverade has two outputs, dogs and cats. this is not a function.

our third option is incorrect as well. the yellow square has two ouputs, the square and the triangle.

lastly, in our fourth option, we see the number 7 two times with a different output. therefore, this is not a function.

remember: each input must be paired with only one output!