Question

Answer this question in 20 mins timer start now or else the question will go away and u would give point 25 points Ready Set GOOOO!!

Answer 1

Answer:

cost of a doughnut is $0.75

cost of a cookie is $0.60

Step-by-step explanation:

As you wrote:
Let x = doughnuts

Let y = cookies

The first sentence of the problem (alexandra) can be written as:

$2x + 3y = 3.30$

The second sentence of the equation (briana) can be written as:

$5x + 2y = 4.95$

We must now solve for either $x$ or $y$ in this system of equations.

I will solve for $x$ in this example.

First we need to multiply the first equation by $2$ and the second equation by $3$. This is so both equations have $6y$ as a term.

Equation 1:

$2(2x + 3y) = (3.30)2\\4x + 6y = 6.60$

Equation 2:

$3(5x + 2y) = (4.95)3\\15x+6y=14.85$

Now that both equations have $6y$ as a term, we can subtract Equation 1 from Equation 2. This will remove y from the equation and allow us to solve for x.

$(15x+6y) - (4x+6y) = (14.85) - (6.60)\\11x = 8.25\\\boxed{x = 0.75}$

We now know the cost of a doughnut is $0.75. Now we can solve for the cost of a cookie through substitution.

$2x + 3y = 3.30\\2(0.75) + 3y = 3.30\\1.50 + 3y = 3.30\\3y = 1.80\\\boxed{y = 0.6}$

Now we know the cost of a cookie is $0.60.

These are the answers,

- Kan Academy Advance