Question

A book cost $x
1. Write an expression in terms of x for the number of books that can be bought from $400?
2. The cost of each book is increased by $20, write an expression in terms of x for the number of books that can now be bought from $400?
3. The number of these books that can be bought from $400 when the cost is increased by $20 is now three-fifths when the cost was $x, write down an equation in terms of x that shows this relationship?
4. Calculate the cost of a book?
5. Calculate the cost of 2 dozen books

Answer 1

Answer:

1. books in $400 = 400/x

2. if cost is increased by $20 then cost of each book = $(20+x)

now books in $400 = 400/(20+x)

3.  400/(20+x) = 3/5(400/x)

----> 5x/3 = 20+x

----> 2x = 60 ==> x = 30

4. x = $30

5. 30*12*2 = $720