Question

Mrs. Schneider purchases twenty donuts and thirty cookies at

a donut shop and is charged $33. Briana purchases five donuts
and two cookies at the same shop for $4.95. All the donuts have the same price. Find the cost of one donut and find the cost of one cookie

Answer 1

The donuts cost $0.75 and the cookies cost $0.6

Explanation:

You need to create a system of equations:

20d + 30c = 33

5d + 2c = 4.95

Now, let's isolate the cookies on the second equation:

2c = 4.95 - 5d

Multiply it per 15 to get the value of 30 cookies:

30c = 74.25 - 75d

Substitute in the first equation:

20d + 74.25 - 75d = 33

-55d = -41.25

d = -41.25/-55

d = 0.75

Now substitute the value of d in the second equation to find the value of c:

5•0.75 + 2c = 4.95

3.75 + 2c = 4.95

2c = 4.95 - 3.75

2c = 1.2

c = 1.2/2

c = 0.6