涛涛GWD25-18

Q18

An equal number of desks and bookcases are to be placed

along a library wall that is 15 meters long. Each desk is

2 meters long, and each bookshelf is 1.5 meters long. If

the maximum possible number of desks and bookcases

are to be placed along the wall, then the space along the

wall that  is left over will be how many meters long?

A.0.5

B.1

C.1.5

D.2

E.3

Answer B

这道题没有看懂的说！

设可摆x张desk，y张bookshelf，

则2x+1.5y<=15，因为x=y，即3.5y<=15 推出以x=y＝4

所以2x+1.5y=14,所以剩下1米，选择b

consider a desk and a bookcase as "one" item, so the left space is the remainder of the following:

15/(2+1.5)   

the remainder is 1---answer B.