求助：prep一道题 怎么算也觉得给出的答案不可能

liludream

192.       18939-!-item-!-187;#058&011984
        怎么求B也求不出来？？？？？

Of the 75 houses in a certain community, 48 have a patio.  How many of the houses in the community have a swimming pool?

 

(1) 38 of the houses in the community have a patio but do not have a swimming pool.

 

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

 

我算出来的是C，怎样算也不可能（2）单独就可以算出来有swimming pool的房子的个数来？

 

请NN出马

aeoluseros

假设P和S都有的人家有x家，那么x=75-s-p+X

所以S+P=75,而P=48，S就等于27