## Tuesday, October 20, 2009

### Brianna's BOB, Ratios

Today in class we talked about the three different types of ratios. We had to come up with questions and ratios using this picture.

Part to Part Ratio:

Greens to Blues
3:3

Odd Colours to Common Colours
9:3
To make 9:3 into a equivalent ratio, you would have to divide 9 by 3 and then divide three by three. Your ratio will then be 3:1.
Part to Whole Ratio:
Blues to Total
3:12
3:12 is 25% and that as a decimal is 0.25.
As a fraction is can be shown as 3/12.
Total to Greens
12:3
Three Part Ratio:
Gold to Silver to Total
1:1:12
Salmon to wild Strawberry to Blues
1:1:3
Three Questions:
1. What are some other ways to make 9:3 into a equivalent ratios?
2. Show three other three part ratios.
3. What are other part to part ratios?
BOB Part 2
One of my mistakes was not putting the ratios in lowest Terms. For example:
A normal deck of playing cards has 52 cards in four suits (clubs, diamond,spades, hearts) of 13 cards each. Two suits are black and the other two are red. The ratio of red cards to the whole deck is: a)1:1 b)1:2 c)2:3 d)2:4
I was supposed to put my answer in lowest terms but I forgot to do that and then I got the question wrong. But now I know that even though sometimes in the question it won't say to put it in lowest terms, but I'll always remember to do it anyways.
Another one of my mistakes was that I forgot that if the numbers in a three part ratio aren't divisible by the same number than you can't break them down into lowest terms. For example:
A stable has 39 horses available for trail rides. Of these horses, 26 horses are all brown, 8 are mainly white and the rest are black. Express in lowest terms the ratio of brown horses to mainly white horses to black horses.
a)13:4:2 b)13:4:5 c)26:8:5 d) 39:26:8
This question couldn't be put in lowest terms because all only two out of three numbers were divisible by the same number , but I didn't realize that until I got my test back.
My third mistake was that I guessed without checking over my answer. For example:
A survey of students in the school found that 144 had Motorola cell phones, 60 had Sony phones, 48 had Nokia phones, and 36 had LG phones.
What percent of all the phones were Motorola?
a)14.4% b)25% c) 50% d) 77%
I got this question wrong because I didn't take the time to add up all the numbers to find out the total. When I saw Motorola had 144, I assumed it was 77%.
Two questions that gave me difficulty:
1. Eric is able to stop 50% of the shots on goal. If he faces 26 shots on goal, how many goals would likely be scored on him?
2. In a group of 100 students surveyed, the ratio of students preference is 5 oatmeal eaters, 3 granola eaters, and 2 Toasted O eaters.
Of the 100 students how many prefer oatmeal?
How many prefer Granola?
What is the percentage of students that prefer Toasted O's?

1. Good job Brianna!

1) 3:1 -or- 6:18

2) -3:7:9
-2:4:8
-1:5:12

3)4:9 -or- 4,9:14

2. 1)1:3

2)1:2:3
4:5:6
7:8:9

3)8:2 or 4:1

3. Q1
-18:6

Q2
-blues to yellow to purple 3:2:1
-green to blue to red 3:3:2
-gold to silver to red 1:1:2

Q3
-purple to yellow 1:2
-green to red 3:2