how do I solve the problem listed below (Description)?

Question

 

In a bowl, there are 16 chocolate chip cookies and 23 grape cookies. How many cookies to grapes must be removed so that 80% of the new contents of the bowl are chocolate chip cookies?

Answer 1

Grape cookies?!  Crazy!  Maybe oatmeal raisin...

 

Anyway, you need to recognize that 80% is 0.8 and is also the ratio of 4/5.

 

If you want 80% of the cookies to be chocolate, then there must be 4 out of 5 cookies are chocolate.

 

So, if the bowl had 5 cookies, 4 are chocolate and 1 is grape.

 

Multiplying both values 4, a bowl with 16 chocolate and 4 grape would still be 80% chocolate chip.

 

You can figure out how many to remove.

Answer 2

Total nimber of cookies = 16+23=39

 

23 is 80 % of what?

 

=28.75=29

 

so total number of cookies must be 29

 

so choclate cookies + grapes cookies = 29

23 +grapes cookies =29

grapes cookies =6

so you have to remove 16-6=10 grapes cookies