Alexis has some dimes and quarters.

Her coins have a total value of $5.80

She has a total of 40 coins

Which of the following systems of equations can be used to find the number of dimes, d, and the number of quarters, q, that Alexis has?

A. d+q=5.80 40d+40q=5.80

B. d+q=40 5.80d+5.80q=40

C. d+q=5.80 0.10d+0.25q=40

Step-by-step explanation:

make two equations

one equation is about the money and one is about counting how many coins

Money equation :.10d +.25q = 5.80

this assigns the value of the dimes at 10 cents and the value of the quarters at 25 cents.

counting equation: d + q = 40

so the answer is C

C. d + q = 5.80

0.10d + 0.25q = 40

Step-by-step explanation:

We are given a situation where Alexis has some dimes and quarters, all her coins have a value of $5.80 / and have a total of 40 coins.

So lets look at the equation for 40 coins.

We are looking for how many dimes and quarters equal to $5.80 and make up 40 in total

Therefore:

We have to add dimes and quarters together to make up $5.80 dollars

d + q = 5.80

This makes B. Incorrect because it has d + q = 40 instead of d + q = 5.80

Now for the amount of coins in total.

We have to find the amount of each coin costs. So a quarter is 25 cents, and a dime is 10 cents. So we add those together to make up 40 coins in total.

0.10d + 0.25q = 40

A. becomes incorrect because is has 40d + 40q = 5.80, which already goes over the amount asked and does not have the correct system of equation.

Therefore leaving you with C.