Given:
Cost to build a bookshelf = $20
Cost to build a table = $45
Amount available to spend = $600
Let x = number of bookshelves built.
Let y = number of tables built.
The total number of bookshelves and tables = 18.
Therefore
x + y = 18.
That is,
y = 18 - x (1)
The total amount available to build x bookshelves and y tables = $600. Therefore
20x + 45y = 600
That is (dividing through by 5),
4x + 9y = 120 (2)
Substitute (1) into (2).
4x + 9(18 - x) = 120
4x + 162 - 9x = 120
-5x = -42
x = 8.4
From (1),obtain
y = 18 - 8.4 = 9.6
Because we cannot have fractional bookshelves and tables, we shall test values of x=8, 9 and y=9,10 for profit
Note: The profit is $60 per bookshelf and $100 per table.
If x = 8, then y = 18-8 = 10.
The profit = 8*60 + 10*100 = $1480
If x = 9, then y = 18-9 = 9.
The profit = 9*60 + 9*100 = $1440
The choice of 8 bookshelves and 10 tables is more profitable.
Answer: 8 bookshelves and 10 tables.
I'm pretty sure it's x/4=y
F(x) = x/2
g(x) = x - 3
f(8) = 8/2 = 4
g(f(x)) = 4 - 3 = 1
Answer g(f(8)) = 1
