Sarah
8th grade student

Out of 200 fish, 99% are guppies. How many guppies must be removed to have 98% of the remaining fish to be guppies?

Hi Sarah,

I think that is easier to concentrate on the fish who are not guppies. 99% of the 200 fish are guppies so 1% are not guppies. 1% of 200 is 1/100 times 200, that is 2 of the fish are not guppies.

You are now to remove enough guppies so that 98% of the fish that remain are guppies, that is 2% of the fish that remain are not guppies. Thus the 2 fish that are not guppies form 2% of the fish that remain. But 2 is 2% of 100 so 100 fish remain. Since you started with 200 fish and now have 100 fish you must have removed 100 fish

Cheers,
Penny
 

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