andy has 23 coins worth 3.65 consisting of only quarters and dimes.how manydimes does he have?

=3.42

q+ d = 23 or d = 23-q

25q + 10d = 365 or
5q + 2d = 73

sub in d = 23-q

5q + 2(23-q) = 73
5q + 46 - 2q = 73
3q = 27
q = 9
then d = 14

She has 14 dimes

check:
9(25) + 14(10) = 365 YEAH!

To find out how many dimes Andy has, we can use a system of equations. Let's denote the number of quarters as 'q' and the number of dimes as 'd'.

1. We know that Andy has a total of 23 coins. So the first equation is:
q + d = 23

2. We also know that the total value of the coins is $3.65. Quarters are worth $0.25 each and dimes are worth $0.10 each. So the second equation is:
0.25q + 0.10d = 3.65

Now we have a system of equations. We can solve it using various methods, such as substitution or elimination. Let's use the substitution method:

From the first equation, we can solve for q:
q + d = 23
q = 23 - d

Now, substitute this value of q into the second equation:
0.25q + 0.10d = 3.65
0.25(23 - d) + 0.10d = 3.65
5.75 - 0.25d + 0.10d = 3.65
5.75 - 0.15d = 3.65

Simplify the equation:
-0.15d = 3.65 - 5.75
-0.15d = -2.1

Divide both sides by -0.15 to solve for d:
d = -2.1 / -0.15
d = 14

So Andy has 14 dimes.