Five apples and four oranges cost $11.80. One apple and six oranges cost $9.90. how much does one orange cost?

the cost of orange is 170

One orange costs $1.45.

Step-by-step explanation:

Since there are two variables, you have to set up a 2 variable equation.

Let's let a = apples and o = oranges.

So, we can set up this problem as:

5a + 4o = 11.80

1a  + 6o = 9.90

You can solve a 2-variable equation using either elimination or substitution. Here, I think it's easier to use substitution. To do that we have to substitute one variable with an equation that uses only the other so that we only have one variable.

We can manipulate our second equation so that it is:

a = 9.90 - 6o

Then, we can plug this in for a in the first equation. So,

5 (9.90 - 6o) + 4o = 11.80

49.5 -30o +4o = 11.80  (Distribute the 5)

49.5 - 26o = 11.80  (Combine like terms)

-26o = -37.7 (Subtract 49.5 from both sides)

o = 1.45 (Divide by -26)

o = 1.45

So, an orange costs $1.45.