Answer:
20 green pencils
Step-by-step explanation:
The difference between black and green "ratio units" is 7 -5 = 2. The difference between red and blue ratio units is 3 -2 = 1. The sum of those differences is 2 +1 = 3 ratio units, which represent 12 pencils. Then each ratio unit represents 12/3 = 4 pencils.
The 5 ratio units of green pencils represent 5·4 pencils = 20 green pencils.
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If you need an equation, you can use k as the constant of proportionality. Then the sum of differences described is ...
(7k -5k) + (3k -2k) = 12
3k = 12 . . . . simplify
k = 4 . . . . . . divide by 3
5k = 5·4 = 20 . . . . . number of green pencils
Answer:
Step-by-step explanation:
Let's take a real situation. Suppose he has 1500 books in total
2/3 of them are fiction. Of means multiply.
them = 1500
2/3 * 1500 = 3000/3 = 1000
Now of the one thousand fiction books 4/5 of them are mysteries.
4/5 * 1000 = 4000/5 = 800.
Now let's see what happens when we just do this by answering the question directly.
2/3 * 4/5 = 8/15 This has the meaning that 8 out of every 15 books = mysteries.
Try this on the 1500 books.
8/15 * 1500 = 9000/15 = 800. So the answers are the same and the answer the computer expects should be 8/15 or 0.533333333
Just to check, does 0.5333333 * 1500 = 800? Try it.
