Hi,

You clearly made a mistake in writing the question so I will assume that the question reads "1/5 of the cats and 1/4 of the dogs". The problem here is that we do not have the ratio of dogs to cats but we know that the number of pets adopted would be higher if the ratio of dogs to cats was higher (because 1/4 of the dogs were adopted versus only 1/5 of cats).
Let's plug some numbers: if we had 50 dogs and 5 cats, then 1 cat would have been adopted and 12.5 dogs. Clearly the number of dogs and cats adopted has to be a whole number, so this mix does not work. If we had 40 dogs and 15 cats, then 3 cats and 10 dogs would have been adopted with a total of 13 animals adopted.

shibal wrote:on monday, a certain animal shelter housed 55 cats and dogs. By friday, 1/5 of the cats and 1/4 of the cats had been adopted; no new cats and dogs had been brought to the shelter. What is the greatest possible number of pets that could have been adopted from the animal shelter btween monday and friday?

OA 13