Tuesday, October 20, 2009

Harvey's BOB ratio

http://www.flickr.com/photos/dmal/2975480134/


BOB about Ratios

Part to Part Ratios
Yellow to Gray--------------2:3
Orange to Green------------2:2
Pink to Blue-----------------1:4

Part to Total Ratios
Yellow to Total-------------2:22
Orange to Total------------2:22
Blue to Total---------------4:22

Three Part Ratios
Yellow to Green to Pink----2:2:1
Gray to Orange to Blue----3:2:4

How to write a ratio 3 other ways

I'll use My Pink to Blue Ratio. (1:4)

There are 3 other ways to write a ratio. As a fraction, decimal, and a percent.

Fraction
To write 1:4 as a fraction, all you have to do is put the number on the left side of the ratio on the top (numerator) and the one on the right on the bottom (denominator)


Decimal
Now, to write the ratio 1:4 as a decimal, you need its fraction form, 1/4. What you basically need to do is divide 1 by 4. You know that line in between the numerator and denominator? That means divide the numbers.

Percent
To make things a lot easier, use the decimal form.
1.00 is the same as 100%. Take away the decimal (pretend you did) and it looks like a 100! So just take away the decimal (always pretend) and you got your answer.

(Blogger has problems uploading my picture)

Ratio Notation
A ratio notation is this: 1:4 the colon in the middle of the numbers. The only thing I know it does is that it shows you that its a ratio.

Equivalent Ratios
Equivalent ratios are what they are, ratios that mean the same thing as the original ratio. An easy way that I know of is to simplify the ratio then multiply it.

I'll be using 2:3 as an example. (Yellow to Gray)

2:3 (Uh Oh, it can't be simplified so we multiply. Remember, what you do on one side you do to the other side.)

2:3 x2
4:6 x2
8:12 x5
40:60 ÷20
2:3

See?

Review:

1) A part to part ratio compares different kinds of groups. T or F?

2) Fractions and part to part ratios are the same. Explain why.

3) Name the probably only mistake you cn make with ratios.

That is all. Good Luck on the test tomorrow!

BOB2
Some things that I got wrong on the test were....

Question 7. I put 2:3 when the acual answer is 18:12.

Question 14. We were supposed to put the percent as a decimal (0.21%) but I just put 21%.

Question 17. All I put as an answer was a word ratio.

Question 18. I put the answer and a little bit of work, but I needed more information so I only got 2/5 for that.


Some Questions..

A rapid transit has 42 passengers on it as it starts to run. At the first stop 16 passengers get off and 9 passengers get on. What is the ratio of the number of passengers who were on the train as it arrived in the first station to the number who were on the train when it left the first station? Express your answer in lowest terms.

In a student election Carol gets 30% of the votes. If there were 975 Votes cast, how many votes did Carol get?

2 comments:

elijah841 said...

1) A part to part ratio compares different kinds of groups. T or F?

False, because it's not comparing different groups, it's comparing other parts in a group together.

2) Fractions and part to part ratios are the same. Explain why.

It's the same because You just have to put the number on the left to the numerator and the number on the right to the denominator.

example :
3:4 - 3/4

3) Name the probably only mistake you cn make with ratios.

If the question says, blue (4) to green (5).
And you put the 5 ahead of the 4. Then it's wrong. It's supposed to be 4:5..

Harvey841 said...

ANSWERS

1) F because p to p compares data from the same group

2) I don't think so because 'normal' fractions are actually part to whole ratios.

3) putting the numbers in the wrong order.

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