Eder needs 15 cookies and 5 brownies.
Given in the question is Eder needs 6 cookies and 2 brownies for 4 plates.
We have to calculate the cookies and brownies required for 10 plates.
Let's first calculate the cookies by unitary method.
∵ 4 plates required cookies = 6 cookies
∴ 1 plate will require cookies = 6/4
∴ 10 plates will require cookies = 6×10/4 = 15
Similarly we will calculate the brownies.
∵ 4 plates required number of brownies = 2
∴ 1 plate will require = 2/4 brownies
∴ 10 plates will require = 2×10/4 = 5 brownies
Therefore 15 cookies and 5 brownies will be required for 10 plates.