Mrs. Ferrario's class needs 5 leaves each day to feed 2 caterpillars.How many leaves does she need each day for 12 caterpillars

Question

I need an expression

Answer 1

 

 5        ?

--- = -----

 2       12

 

Now you can solve this proportion by equal ratios method or 

cross multiplication

 

You multiply the bottom by 6 as 12/2 = 6

So the top is 5*6 = 30

 

Cross multiplication 5*12 =  ? * 2

                              60 = ? * 2

                              ? = 30

                             

The answer is 30