Guppies

If you have 200 fish and 99%of them are guppies, how many do you have to remove to make them equal 98%?

 

200 x .99 =198 are guppies and 2 are non-guppies

200 x .98 =196 would be guppies and 4 would have to be non-guppies

198 - 196=2  guppies you would have to remove BUT, they must be replaced with 2 non-guppies, if you want the number of fish to remain at 200.

If you have 200 fish and 99% of them are guppies, how many do you have to remove to make them equal 98%?

 

Since 99% of the fish are guppies, you have  200 x 0.99  =  198 guppies  and  2 fish that aren't guppies.

 

Let  x  =  number of fguppies that you remove.

Then, you will have  198 - x  guppies  and  200 - x  fish (total).

 

Since you want the percentage of guppies to be 98%:

     percentage of fish that are guppies is:  guppies / total fish   

So:  (198 - x) / (200 - x)  =  0.98

Cross multiplying:     198 - x  =  0.98(200 - x)

--->                           198 - x  =  196 - 0.98x

--->  Simplify:            198 - 196  =  x - 0.98x

--->                                         2  =  0.02x

--->                                         x  =  100 guppies.

 

So, remove 100 of the guppies and you will have 98 guppies out of a total of 100 fish; this is 98%.