At a cupcake shop, they make 3 chocolate cupcakes for every 4 vanilla cupcakes. If they make 270 chocolate cupcakes, how many vanilla cupcakes will they make?

Question

Create a table of values and graph each scenario.  Determine if each scenario is proportional or not and explain why.

Answer 1

set up a proportion

3 chocolate/4 vanilla=270 chocolate/? vanilla

3/4=270/n

cross multiply or use equal fractions

3*n=4*270

3n=1080

n=1080/3

n=360 vanilla cupcakes

or,...

3/4=270/n

3*90=270 so 4*90=360 vanilla cupcakes again

Answer 2

There's a few ways to look at this but here is the easiest. Pretend you make 7 (3+4) groups of cupcakes at a time..3 chocolate and 4 vanilla. 

 

Divide the total number of cupcakes by each group. 

270/7= 38.5

 

There are 38.5 cupcakes in each group. 

38.5 X 3 = 116. There are 116 chocolate cupcakes.  

 

38.5 x 4 = 154. There are 154 vanilla cupcakes. 

You can double check this:

116+154 = 270. Also, if you have 3 chocolate to 4 vanilla. 3/4=.75. 116/154=.75!