a recipe for a batch of 3 dozen chocolate chip cookies calls for 3 1/2 cups of flour, 1 cup of sugar, and 2 3/4 cups of chocolate chips. How much of each ingredient should be used to make 2 dozen cookies?

Respuesta :

3 doz = 36 cookies, 2 doz = 24 cookies

36/3.5 = 24/x
36x = 84
x = 84/36
x = 2.33 = 2 1/3.......so for 2 doz, u need 2 1/3 cups flour

36/1 = 24/x
36x = 24
x = 24/36
x = .666 = 3/5...and 3/5 cup of sugar

36/2.75 = 24/x
36x = 66
x = 66/36
x = 1.83 cups of chocolate chips

Answer:

Step-by-step explanation:

A recipe for a batch of 3 dozen chocolate chip cookies calls for [tex]3\frac{1}{2}[/tex] cups of flour, 1 cup of sugar and [tex]2\frac{3}{4}[/tex] cups of chocolate chips.

We will calculate for each ingredients by unitary method.

∵ flour used in 3 dozen cookies = [tex]3\frac{1}{2}[/tex] or [tex]\frac{7}{2}[/tex] cups

∴ flour used in 1 dozen cookies = [tex]\frac{7/2}{3}[/tex] cups

∴ flour used in 2 dozen cookies = [tex]\frac{7/2}{3}[/tex] × 2

                                                     = [tex]\frac{7}{6}[/tex] × 2

                                                     = [tex]\frac{14}{6}[/tex]

                                                     = [tex]\frac{7}{3}[/tex]

                                                     = [tex]2\frac{1}{3}[/tex] cups

∵ sugar is used in 3 dozen cookies = 1 cup

∴ sugar is used in 1 dozen cookies = [tex]\frac{1}{3}[/tex]

∴ sugar is used in 2 dozen cookies = [tex]\frac{1}{3}[/tex] × 2

                                                           = [tex]\frac{2}{3}[/tex] cups

∵ chocolate chips are used in 3 dozen cookies = [tex]2\frac{3}{4}[/tex] = [tex]\frac{11}{4}[/tex] cups

∴ in 1 dozen cookies chocolate chips used = [tex]\frac{11/4}{3}[/tex]

∴ in 2 dozen cookies chocolate chips used = [tex]\frac{11/4}{3}[/tex] × 2

                                                      = [tex]\frac{11}{12}[/tex] × 2

                                                      = [tex]\frac{11}{6}[/tex]

                                                      = [tex]1\frac{5}{6}[/tex] cups

To make 2 dozen cookies each ingredient should be used :

[tex]2\frac{1}{3}[/tex] cups of flour

[tex]\frac{2}{3}[/tex] cups of sugar

[tex]1\frac{5}{6}[/tex] cups of chocolate chips