Five donuts and 3 cinnamon rolls cost $11.50. eight donuts and 6 cinnamon rolls
cost $20.50. how much does a donut cost? how much does a cinnamon roll cost?

The cost of one donuts is $1.25 and the cost of one cinnamon is $1.75

Step-by-step explanation:

Let

x-----> the cost of one donuts

y ----> the cost of one cinnamon

we know that

-----> equation A

-----> equation B

Solve the system by graphing

Remember that the solution of the system of equations is the intersection point both graphs

using a graphing tool

The solution is the point (1.25,1.75)

see the attached figure

therefore

The cost of one donuts is $1.25 and the cost of one cinnamon is $1.75

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!