Example 6: If there are 20 books in this batch, they should be bundled into 18 package. If there are 30 copies in a package, how many packages should I bundle?
The girl said, "I'll calculate a * * first, how many books are there, and then I'll calculate …"
The boy said, "It can also be solved in proportion."
Because the total number of books is certain, the number per Bao Shu is inversely proportional, that is, the product of the number per Bao Shu and the number of packages is equal.
Solution: Suppose you want to bundle X packages.
30X=20* 18
X=20* 18/30
X= 12
Answer: We need to bundle the 12 package.
If you want to bundle 15 packages, how many copies per package?
Do it:
1, Xiaoming bought four ballpoint pens and used 6 yuan. Xiaogang wants to buy three identical ballpoint pens. How much will it cost?
There are two kinds of ballpoint pens in the school shop. Xiao Ming has just enough money to buy four pieces, and the unit price is 1.5 yuan. If he wants to buy it all, the unit price is 2 yuan. How many pieces can he buy?
I wish you progress in your study. Don't leave your book at school!
Hope to adopt! ! !