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?
The way I approached this problem is much more simplistic than the answers otherwise listed. We know that the length available to be filled is 15. I then chose to see how many desks/book shelfs can be placed:
1.5Bookshelf = 15
Bookshelf = 10
2 Desks = 15
Desks = 7 (the answer is 7.5, but you can not place half a desk there)
Max bookshelves that can be placed = 15 (assuming no desks) and maximum desks that can be placed = 7 (assuming no bookshelves). Since the value of max bookshelves > max desks, we want to maximize the # of bookshelves by using only 1 desk.
2(1) + 1.5(x)= 15
1.5x = 13
x = 8 (rounded down to the nearest whole number)
So we know that we will have 1 desk and 8 bookshelves. Now you just calculate 2(1) + 1.5(8) = x.
and then 15 - x = answer, which happens to be the value 1, aka B.