Answer:
12 books
Step-by-step explanation:
Since she has $15 and books come in a pack of four for $5, we can divide her money by the cost to see how many she can get ($15/$5) which gets us 3. but we have to remember the books come in a pack of four so we must multiply 3x4=12 books.
20 divided by 40=2
20x40=800
800 divided by 40= 20
All you have to do for this is follow the midpoint formula.
Let me know if the picture is unclear and I'll type it out for you.
It is subtracting the current number by 1/2 OR you can divide by 2. each time.
32 / 2= 16
16 / 2=8
8/2=4
4/2=2
2/2=1
Hope this helped!