john has a total of 18 stamps which consists of 25 cents and 2 cent stamps they have a value of $2.20 how many of each do you have?

x = 18 - y

.25x + .02y = 2.20

Substitute 18-y for x in the second equation and solve for y. Insert that value into the first equation to solve for x. Check by putting both values into the second equation.

To solve this problem, we can set up a system of linear equations. Let's use the variable x to represent the number of 25 cents stamps and y to represent the number of 2 cent stamps John has.

We are given two pieces of information:

1. John has a total of 18 stamps, so:
x + y = 18

2. The total value of all the stamps is $2.20, so:
0.25x + 0.02y = 2.20

Now we have a system of two equations:

x + y = 18
0.25x + 0.02y = 2.20

We can solve this system of equations using various methods (substitution, elimination, or matrix methods). In this case, let's use the substitution method.

From the first equation, we can solve for x:
x = 18 - y

Now substitute x in the second equation:
0.25(18 - y) + 0.02y = 2.20

Distribute 0.25:
4.5 - 0.25y + 0.02y = 2.20

Combine like terms:
4.5 - 0.23y = 2.20

Subtract 4.5 from both sides:
-0.23y = -2.30

Divide by -0.23:
y = 10

Now substitute y back into the first equation to solve for x:
x + 10 = 18
x = 8

Therefore, John has 8 of the 25 cents stamps and 10 of the 2 cent stamps.