Question

某图书馆有科技书和文艺书共800本,如果文艺书再增加1/5,科技书再增加1/9,则现在两种书共920本,原来两种书各多少

Answer 1

设科技书有x本,则文艺书有800-x本,依题意有：

(800-x)*[1+(1/5)]+x*[1+(1/9)]=920

===> (800-x)*(6/5)+x*(10/9)=920

===> 960-(6/5)x+(10/9)x=920

===> (6/5)x-(10/9)x=40

===> (4/45)x=40

===> x=450

所以,800-x=350

即,原来文艺书有350本,科技书有450本.