From a shipment of 500 Eveready vampire bunnies, a sample of 25 was selected at random and tested. If the batteries in two of the bunnies were found to be dead, how many dead vampire bunnies would be expected in the entire shipment?



While a reasonable tongue-in-cheek answer to this problem could have been that they're all dead... after all, they're VAMPIRE bunnies.... this was really a simple problem which asked the question "if 2 out of every 25 batteries are dead, how many dead batteries could be expected out of 500?



Out of 500 batteries, where 2 out of 25 are dead, expect 40 dead batteries.
Or, you might have thought to yourself:

"If 2 out of every 25 vampire bunnies have dead batteries, then 2x4=8 out of every 100 vampires bunnies would have dead batteries, so 8x5=40 vampire bunnies would have dead batteries in a batch of 500 vampire bunnies."

"If there are 500/25 = 20 sets of 25 vampire bunnies, each set with 2 bad batteries in them, then 2x20=40 vampire bunnies would probably have bad batteries."

"If there is 1 bad battery for every 25/2 = 12.5 vampire bunnies, there are 500/12.5 = 40 bad batteries in the whole batch."

"If 2/25=.08 (=8%) of the vampire bunnies have dead batteries, then 500x.08=40 vampire bunnies would be expected to have dead batteries."