Luis is saving money to purchase a new video game. he has a total of 30 coins consisting of nickels and dimes. the value of the coins is $2.20. let n represent the number of nickels and let d represent the number of dimes. which system of equations can be used to determine the number of nickels and the number of dimes luis has?

and

Step-by-step explanation:

Let n represent the number of nickels

Let d represent the number of dimes.

Luis has a total of 30 coins; equation becomes:

or   ..... (1)

The value of the coins is $2.20 ; equation becomes:

{a dime is worth 10 cents and a nickel is 5 cents}

  ..... (2)

Putting the value of n from (1) in (2)

=>

=>

=>

=> d=14

And n=30-d

so,

So, the system of equations used to determine the number of nickels and the number of dimes Luis has are :

and

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40