救命阿 等等考 卻忘了這題怎麼做

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.怎麼求?

Ans: B

设都有的那部分为t，可列出等式75-t=48+-t